Of the immense value of the recent deep-sea soundings there can be no doubt, but whether geologists will side with Dr. Carpenter in the deductions he has attempted to draw from these explorations seems to me a matter of considerable doubt: and I propose to discuss here several difficulties that have occurred to myself on this head. I shall take as my text Dr. Carpenter's last exposition of his views in a letter to Nature of Oct. 27th.

The Marine Invertebrate Fauna of the Lias would, if one consulted Morris's Catalogue of British Fossils, published in 1854, be regarded as exceedingly poor, especially in certain classes, relative to the thickness of the rocks constituting that system. Thus, I count, eliminating synonyms, 130 species of Cephalopoda, 5 of Gasteropoda, 57 of Conchifera, 37 of Brachiopoda, 1 of Crustacea, 2 of Annelida, 21 of Echinodermata, and 2 of Zoantharia, and if to these we add the fish and other forms of life, we obtain a total of 426 species of plants and animals. But during the lapse of 16 years, this number has been nearly tripled, and to those classes, which were either unrepresented or characterized by a paucity of species, great accessions have been made. Notably, the number of Gasteropoda has risen from 5 to 269; the Conchifera from 57 to 297, the Brachiopoda have been augmented by the addition of 39 species, the Corals now number 67, and the Polyzoa and Sponges, previously unrepresented, now have a place in the list.

Whenever a bone is about to be produced in the animal body, its form is first sketched out in connective tissue or cartilage, and then ossification commences at one or several points; if there is but one centre of ossification, or if several centres unite, but one bone is formed; if the several centres do not completely unite, as many separate bones are produced.

Considerable difficulty has been felt in accounting for the transport of the Wastdale Granite Boulders across the Pennine chain to the east. Professors Harkness and Phillips, Messrs. Searles Wood, jun., Mackintosh, and I presume all who have written on the subject, agree that these blocks could not have been transported by land-ice. The agency of floating ice under some form or other is assumed by them all.

The Graptolites for which the name Dicellograpsus is here proposed are usually included in the genus Didymograpsus, which is thus made to comprise two groups of species which are not only generically distinct, but belong to entirely different sections of the Graptolite family, the species properly belonging to Didymograpsus (D. Murchisoni for example) having hydrothecæ similar to those of Graptolithus, while the species erroneously included in the genus (D. Forchhammeri and others) have hydrothecæ of the type of Climacograptus. This was first pointed out by Prof. James Hall. In his “Graptolites of the Quebec Group” (p. 57) he removed these species from Didymograpsus, and placed them in his new genus Dicranograptus; the species previously known as Diplograpsus ramosus being considered the type of the genus. To this species, and to another then first described, the genus was afterwards restricted by Mr. Carruthers, the remaining species being again included in Didymograpsus. Though fully agreeing with Mr. Carruthers in thus restricting Dicranograptus, I cannot consider the species removed from it as having any alliance to Didymograpsus.