14 BRITISH SILURIAN BRACHIOPODA. 
Say has given several MS. names (adopted by Hall) to specimens in the collection of 
the Acad. Nat. Sciences, Philadelphia. 
Dr. D. Date Owen, ‘ Reports of a Geol. Survey of Wisconsin, Iowa, and Minnesota,’ 
1852, and ‘ Annual Geol. Rep., Wisconsin,’ 1860. 
F. Roemer (see Russia and Germany). 
Biessy, “On the Paleozoic Basin of the State of New York,” in the ‘ Quarterly 
Journal of the Geol. Soc.’ for years 1858, 1859. 
De Verneuit, ‘ Bulletin Soc. Géol. de France,’ 2nd series, vol. iv, 1847; and 
vol. v, 1848. 
Pror. Rogrrs, ‘ Geology of the State of Pennsylvania,’ 1858, contains a good deal 
in connection with the Silurian Brachiopoda. 
Dr. B. F. Soumarp has published an account of several American Silurian Brachio- 
poda from the State of Texas, in the ‘Trans. Acad. Nat. Sci. St. Louis,’ vol. 1, 1860; 
also in the ‘Am. Journ. Sci.’ for 1861. I am, moreover, informed that he finds, by looking 
over his list, the names of more than 350 species of North American Silurian Brachiopoda ; 
but of these a large number will have to be classed as synonyms. 
Dr. F. V. Haypen and F. B. Merx give an account of some Silurian Brachiopoda, 
of the age of the Potsdam Sandstone, from near the Black Hills and other localities along 
the eastern side of the Rocky Mountains, in the ‘Am. Journ. Sci.,’ Jan., 1862, also in 
‘ Acad. Sci. Philad.,’ Dec., 1861 ; see likewise the same paleontologists’ ‘ Palaeontology 
of the Upper Missouri,’ published by the Smithsonian Institution, April, 1865, &c., &. 
Notwithstanding all this labour, much, indeed, still remains to be achieved before all 
these British and foreign so-termed species can be satisfactorily illustrated, revised, and 
referred to their proper genera, for the number of synonyms and of incorrectly identified 
forms is considerable: but such a state of things is not, however, surprising; for our 
accurate knowledge of these fossils is not yet so much advanced as to enable the 
paleontologist to grapple with so immensely large and difficult a subject, or to admit of his 
always correctly discriminating or defining a certain number of these still imperfectly 
known so-called species. This desideratum will, no doubt, be attamed in time; and 
the publication of a general monograph, embracing the species from every country, 
will doubtlessly help, though the work cannot be fully and successfully accomplished until 
after many more years of active and intelligent research, aided by fresh discoveries and 
more ample materials. It would, indeed, be presumptuous were I, however much may 
have been my labours and efforts, to pretend that in the present Monograph I could work 
out even our British forms in a completely satisfactory manner, and therefore all I now 
hope to do is to offer to the student the results of our combined knowledge upon the 
subject I have to treat; and this, I trust, may prove to be of some utility, since we 
