386 The American Geologist. June, 1895 
sion of specific values. The portion of this chapter which treats of the 
sponjres is the most lengthy and important. One may wonder how any 
writer could adopt such an incongruous lot of family names as Recepta- 
culitid(e, DietyoKp(mgkl<t', Pharetrones and T'etrachidina without disguising 
the value of the observations here brought together and which are, for 
the most part, those of Mr. E. O. Ulrich. Besides the forms referred to, 
a few species of graptolites and corals are described, among them the 
type of a new genus of Zoantharia, Lichenaria typa. In all, the chapter 
embraces illustrated descriptions and reviews of 21 species; but five of 
these are new, and three of this five are accredited to Mr. Ulrich. 
Chapter IV is "On the Lower Silurian Bryozoa of Minnesota,"' by E. O. 
Ulrich, extends from p. 96 top. 332, and is illustrated with 28 plates. 
This important chapter has already been briefly referred to in the Amer- 
ican Geologist (vol. xn, p. 331) and no appreciative review of its con- 
tentscan now be given. This group of small and complex fossils has so 
long enlisted the author's best activity, that few students have followed 
him closely enough to be entitled to express anything but encomiums up- 
on his accomplishments. The paper opens with introductory pages upon 
the morphology, terminology, preservation and methods of study, clas- 
sification and geological distribution. '"To the Bryozoa." the author 
writes, in his opening paragraph, "must be accorded the first rank 
among the various classes that are represented in the Lower Silurian 
rocks of Minnesota. Thej' are entitled to this distinction, first, because 
of the great variety of form and structure found among them, and, 
second, because of their exceeding abundance." Elsewhere, as here, 
Mr. Ulrich has claimed the Bryo/oa as the best horizon marlvers of the 
earlier Silurian, and he may be fully justified in the claim, even though 
a faunal division on such a basis is beyond the grasp of the majority of 
paleontologists. The descriptions are perspicacious, the observations 
acute and penetrating and the results are of fundamental value. 
Cliapter V, "The Lower Silurian Brachiopoda of Minnesota," by N. 
H. WiNCHELL and Charles ScHUCHERT, covers pp. 333-474 and plates 
29-34. Twenty-nine new species and varieties are described, most of 
these descriptions having already been published in the American Ge- 
ologist. J. M. c. 
The Geolof/t/ of Conanicut Tdand. R. L By G. L. Collie. (Trans. Wis- 
consin Acad. Sci., Arts and Letters, vol. x, [ip. 199-230, pi. 4, March, 
1895.) This is a small island lying in Narragansett bay, just west of 
Newport. The main part of the island consists of a series of schists, 
often graphitic, with some interbedded grits and conglomerates, the 
whole presenting a tliickness of 1,200 feet. In the lower portion of this 
series Carboniferous plants have been found. Unconformably below 
the schist series is a coarse porphyritic biotitc granite and agreen liinty 
slate of unknown age. The granite is of more recent dale than the 
slate. The author presents evidence to show that the above is the true 
structure, in ojjposition to the idea that the schists and the slate are of 
the same age and that the latter is only an altered phase of the former, 
