It is more than a century since the “Dudley Locust,” or ‘Trilobite,’ was first figured and described, 1 and the locality where it it is found, is rendered famous by the researchs and writings of Sedgwick, Phillips, Forbes, Murchison, Salter, Davidson, and a host of other geologists and palæontologists, who have been attracted thither at various times by the grand geological features of the district or by the matchless beauty and endless diversity of its well-preserved organic remains.

It is some months since I read a paper at the Cambridge Philosophical Society, to which reference has been made in your pages by Mr. Maw. I do not think that I shall be out of order in sending you a short outline of the substance of it.

In the course of my recent investigations among the fauna of the Low Main Coal-shale in the county of Northumberland, which lies at an average depth of about 100 fathoms from the surface, I have found among numerous fish and reptilian remains three specimens of teeth that present the appearance of being vomerine in their nature. The tooth here represented in the woodcut, of the natural size resembles exactly in size and form another specimen which I have in my possession, the view exposed being the front aspect of the tooth. I have a third specimen, which exhibits the upper or attached part of the tooth; it has a sharp curved appearance, not unlike the back of a well-written letter S.

In the following brief remarks on the range and distribution of Brachiopoda in British strata, and in the accompanying tables, the classification of Dr. Davidson has been mainly followed; and the calcuations of the numbers have been prinicipally based on the researches of that great authority, though the recent discoveries of Mr. C. Moore and others have been duly taken into consideration. These numbers must, of course, only be regarded as showing the present state of knowledge on the subject, as the active search which many observers are making will doubtless materially alter the figures here given.

No one, I think, will deny that geology is far behind all the other sciences in the classification of those substances which form its special study, viz., rocks. No two authors agree on the subject, and no one seems to have attempted to form a scientific classification, based on a natural system.