We study the freeness problem for multiplicative subgroups of $\operatorname{SL}_2(\mathbb{Q})$. For $q = r/p$ in $\mathbb{Q} \cap (0,4)$, where p is prime and $\gcd(r,p)=1$, we initiate the study of the algebraic structure of the group $\Delta_q$ generated by

\[A = \begin{pmatrix}1 & 0 \\ 1 & 1\end{pmatrix} \text{ and } Q_q = \begin{pmatrix}1 & q \\ 0 & 1\end{pmatrix}.\]

$\Delta_{r/p} = \overline{\Gamma}_1^{(p)}(r)$

$\operatorname{SL}_2(\mathbb{Z}[{1}/{p}])$

$r \leq 4$

$r = 5$

$r \in \{ p-1, p+1, (p+1)/2 \}$

$\Delta_{r/p}$

$J_2(r)$

$\operatorname{SL}_2(\mathbb{Z}[{1}/{p}])$

$J_2(r)$

Biformites insolitus Linck, 1949 and very shallow, partially facetted, vertical burrows occur together in calcareous siltstone as convex hypichnia of sandstone on bedding soles within the Lower Devonian Clam Bank Formation, western Newfoundland. The ichnofossils occur within thinly interstratified siltstone and sandstone that accumulated within a physically stressed, euryhaline, peritidal paleoenvironment. B insolitus consists of straight to sinuous, narrow (2–3 mm), strap-like imprints commonly up to 7 cm long that display a medial axial depression and paired (opposite) conical (rounded blunt tipped) to irregular blocky and rectangular-shaped protuberances. These structures are interpreted to represent the impressions of ophiuroid arms, including representations of tube feet and ambulacral skeletal structure. Ornamentation detail appears proportional to the depth of an imprint and is a measure of the amount of downward force of an arm relative to horizontal motion. Apparent branching of imprints represents arm overprints. Incompletely facetted transverse sections of burrows, also filled with sandstone, warrant comparison with the ichnogenus Pentichnus, but incomplete preservation of a possible higher-order symmetry defers ichnotaxonomic designation. The imprints are very shallow (<1 cm) and fit with very near-surface burrowing as observed among some modern ophiuroids. The burrows are either a variant of Pentichnus, thereby expanding its current stratigraphic range, or broaden a unique ichnotaxobase of facetted burrows. A middle Paleozoic record of B. insolitus narrows the current disparity with the post-Cambrian ophiuroid skeletal record. Its spatial association with burrows in a peritidal paleoenvironment reinforces the complex behavior of ophiuroids, their ecological breadth, and opportunistic behavior.

Bibliographical research on Mali must begin with the monumental Bibliographie générale du Mali, prepared by Paule Brasseur (Dakar, IFAN, 1964). The present essay is in no way a substitute for such a basic volume. It is an attempt to introduce the reader to some of the best and most important works concerning Mali, at the same time stressing materials that have appeared in English or since the publication of the Brasseur work.

Neither the Brasseur bibliography nor this essay takes adequate account of the manuscript sources in Peul and Arabic concerning the western Sudan. Still in private hands or in the archives of Paris, Dakar, Zaria, Kano, Ibadan, or Timbuktu, these manuscripts are largely unclassified and unstudied. Once analyzed, they will provide an important source for the study of Malian history. Vincent Monteil, “Les manuscrits historiques arabo-africains,” Bulletin de l'IFAN, série B, XXVII, No. 3-4 (July-October 1965), 531-542, surveys efforts being made to collect and classify such manuscripts in West Africa. H. F. C. Smith, “The Archives of Segu,” Bulletin of News of the Historical Society of Nigeria, Supplement to Vol. IV, No. 2 (September 1959), presents a brief analysis of some of the great collection of manuscripts captured by Archinard in 1890 and now in the Bibliothèque Nationale, Paris. In addition, in “Source Material for the History of the Western Sudan,” Journal of the Historical Society of Nigeria, I, No. 3 (December 1958), 238-248, Smith surveys significant materials from the Gironcourt Collection, in the Institut de France, Paris. This is updated by him in “Nineteenth-Century Arabic Archives of West Africa,” Journal of African History, III, No. 2 (1962), 333-336, a brief listing of literary works, diplomatic correspondence between West African emirates, etc.

Informed by an international dialogue on sustainable financing for noncommunicable diseases and mental health in 2024, this Editorial explores some of the key financing issues to be addressed in September 2025 at the United Nations General Assembly high-level meeting on noncommunicable diseases and mental health, including those relating to domestic resource mobilisation, external assistance and health financing reforms.

This bibliography is the first attempt to establish a comprehensive listing of the various types of documents which the Liberian government has published. That it is not complete, goes without saying. Only time and further discoveries will make it so. In addition, certain of the gaps which occur are due to the nature of some of the material. Some parts of the series were never duplicated for mass distribution; rather, they remain in manuscript form in the Liberian government archives.

In this bibliography I have limited listings to printed and duplicated materials. I have attempted to follow the Library of Congress form of cataloging where applicable. Where government agencies, although maintaining the same functions, have changed names, the cross references are given. Finally, a notation is given when a specific document is available at a public library.

The American Geographical Society, Broadway at 156th Street, New York, N. Y. 10032, has an African collection of approximately 5,000 volumes, with emphasis on exploration, travel, description, history, and geography, and an estimated 137 linear feet of shelf space of government documents and 100 feet of shelf space for periodicals. The Society holds sets of maps for most African countries as well as numerous single maps for individual countries. The maps date from 1500 to the present time. Subjects covered include geology, soils, population, ethnography, economics, history, and transportation. The approximate number of single maps is 7,000. In addition, the Society has approximately 70 atlases, and a unique catalogue of maps published in periodicals and books is maintained.

Area studies at Yale University, New Haven, Conn., embrace Africa, East Asia, Southeast Asia, Latin America, the Soviet Union, and Eastern Europe. There is also interest in Near Eastern, Indie, and Commonwealth studies. Each area has a curator or adviser to the Library who ensures that all important publications issued in or about his area are secured.

Although the Council on African Studies at Yale goes back only to 1957, interest in Africa extends much further into the past. Individual members of the faculty have pursued Africanist researches from the beginnings of such studies. African history and the African collections in the Yale Library owe much to Professor Harry Rudin. Professor G. P. Murdock and associates founded the Cross Cultural Survey at Yale, out of which grew the Human Relations Area Files. (The complete files of both are housed in the Sterling Memorial Library.)

The purpose of this conference was to discuss the present state of research on human migration and to suggest the most immediate needs for studies facilitating research and for substantive investigations, all with special reference to Africa. The following participants met for two days in Evanston, Illinois: Lyle W. Shannon, of the Sociology Department of the State University of Iowa, has completed a study of in-migration of Mexican-Americans, southern whites, and Negroes to Racine, Wisconsin, and is concerned with the functions of gatekeepers, prevailing opportunities, and experiences of change in the absorption and integration of migrants into their new community. Leonard Doob of the Psychology Department of Yale University has done work with a scale of opinions and values which has been tested with five African tribes; he is particularly concerned with acculturation and imagery as well as temporal orientation and selective migration. Edward Soja from the Geography Department at Northwestern University has been working on Kenya, mapping intranational patterns of migration, and testing the theory that clashes of cultures generate differentiation. Hans Panofsky, Curator of the African Library at Northwestern University Library, has been concerned with the economic aspects of labor migration in Ghana and bibliographically with the whole of Africa. Louise Holborn, of the Political Science Department of Radcliffe College, has been working with the refugee problem, UN resettlement projects, and international migration. Leo F. Schnore, sociologist from the University of Wisconsin, has been doing research on population redistribution and residential mobility in the United States. Francis Hsu of the Anthropology Department of Northwestern University and Duane Marble of the Geography Department were with the group briefly. Marilyn Tschanner and Roland Eves served as rapporteurs. Chairman was Franklin D. Scott of the History Department of Northwestern, who has worked on migration in general and especially on Scandinavian migration and cultural interchange.

This listing of recent African atlases is supplementary to that published in thisBulletin, October 1962. As in that article, atlases have been grouped according to major areas covered, and contents classified. Subject headings are: historical (hist.), physical and terrain (phys.), geology (geol.), climate (dim.), vegetation (veg.), soils, hydrography and irrigation (hydro.), political and administrative (pol.), agriculture and land use (agric.), forestry (for.), minerals and mining (min.), transportation (trans.), communications (commo.), miscellaneous economic (misc. econ.), population (pop.), tribes and races (trib.), languages (lang.), religious (relig.), health and diseases (health), African regions (regional), city and vicinity (city), other African subjects (other sub.), and non-African or extra-regional areas (other areas).

This analysis is based mainly upon atlases examined at the Map Division in the Library of Congress, the American Geographical Society in New York, and the University of California, Los Angeles. This article is part of a research project supported by the African Studies Center at UCLA. The authors welcome comments on errors or omissions.