Geology and Mineralogy. 227 



profusion of crinoids and the enormous area of the Carbonic* n.us 

 indicates, he remarks, a wide, warm, and comparatively shallow 

 ithe jlnlln-can remains being quite large) sea, its waters richly 

 charged with carbonate of lime. 



Prof. Shaler discusses at length the age of the caverns and 

 states as his conclusion that probably ".while some caverns may 

 have existed in the Mississippi valley long before the Tertiarv 

 period, their great development, with the consequent c' 

 organic life finding its way into ca 



The i bird is b v Prof. Shaler and is the first of a series on the 

 f«>ssil Brachiopods of the Ohio valley. The author, in this paper, 

 takes up tin \ < r\ impi.rtant questimi ot amount of variation in 

 some of the more variable -peeies. and presents tables of measure- 

 ments, iu addition to detailed remarks on the different chura.-t, rs 

 and the distribution of" the species. For example, w 



localities are given, including dimensions as to length ami width 

 <'f shell, length of liingedine and of muscular impression, width 



fore an important <•-'' ot ' tlie variation ot 



species. The*, variations m uomhrtu >gr. ' i «: ■ ■<- -• 



Thus in the above speei.s tl < prop, tion in h-ngrli to u i r h ^ ies 

 from 1 : 1-05 to 1 : l-5o. This article is illustrated by seven plates, 

 prepared, like other plate- of the volume, bv the autotype process, 

 which avoids all error of drawing; and it is stated b> ' 

 that he first bedded tin <p.-ciinci - in \\ > t. «and. thereby doing 

 away with the shadow* which make one of the difficulties in prop 

 erly taking a photograph for this process. 



The fourth u< an and Prof. Shaler. treat, 



of the prehistoric remains of Kentucky. It contains a \ cry judi- 

 ( '">m discussion of the value of the remains in North Amen -a as a 

 measure of time, together with other interesting d.- \ 



mows, which "volume will contain also, a- announced in Me 



Preface, tb< m mow: t* the 1 



" !; ! >«- Dynamic Geology of Kentucky, 1 y 



( :i yern Animals of Keiituekv, by A. S. Pa< kai:k V . -\ 



; ^<! others; ,,„;), , , . , ,, ,., | u , | | „ .■ 1 baces ot Kentucky by F. \V . 



1\ WAM . Cavern Animals, by 



The Memoirs published by the Survey on purely scientific sub- 



