80 Annals of the Carnf.oie Museum. 



by Dr. John M. Clarke to contain fossils, whose shells had been so 

 completely replaced by silica, that, when the rock was etched in acid, 

 the shells were left in as perfect condition as they were when buried 

 in the limey clay of their native sea-botto,m. A large quantity of the 

 material was obtained by Professor C. E. Beecher and through his 

 kindness the writer was given an opportunity to study a part of it. 

 About sixty-five pounds of this rock was treated with hydrochloric acid 

 and the shells separated by washing from the clay which remained 

 after the calcium carbonate had been removed. About fifteen thou- 

 sand nearly perfect specimens were selected and a much greater quan- 

 tity of fragmentary material discarded. Nearly all classes of inverte- 

 brate animals were represented in this collection, but the brachiopods 

 were most numerous, composing fully two-thirds of the total number 

 of individuals. There are as many as thirty-five hundred specimens 

 of one species i^Chonctes scifi/Ius). Next in abundance to the 

 brachiopods were the Bryozoa, then the Crustacea, worm tubes, 

 Pelycypoda, Gastropoda, Anthozoa, and Cephalopoda in the order 

 named. The Echinoderms are represented only by crinoid columns. 

 There were also a few fish scales and sponge spicules found. Chitinous 

 shells of the Liiii^u/a type do not appear to have been preserved and 

 some of the Dimyarian bivalves occur only as casts. 



The majority of the shells are white, but some are dark gray to 

 blacTc and the trilobite tests are light to dark brown. The color seems 

 to be fairly uniform for all the individuals of the same species. For 

 instance, there are two species of Monofrypa, and all the individuals 

 of both species are black, while most of the Bryozoa are light col- 

 ored. But in the case of Chonetes imicionatits, whereas most of the 

 specimens are dark, a few are light. 



The state of ])reservation of the fossils in this material is remarkable, 

 even the finest details being retained, which shows conclusively that 

 the shells were not subjected to any rough wave action after the death 

 of the animal. The graceful fronds of the Fenestellidje are obtained 

 as they grew, and the delicate spines of the Productidce and the spini- 

 form extensions of the cardinal angles of the young Stropheodontas 

 are perfectly preserved. Unfortunately the brachial loops and spires 

 are not so well preserved, though many specimens of Eiiue/la show a 

 large part of the loop and in one young specimen it is entire. ^lany 

 specimens of 7)-opidoIcptiis retain the delicate median septum and the 

 crura but the full looj) was not observed. 



