312 



GEOLOGY OF THE SECOND DISTRICT. 



same orders, and animals adapted to the same state and conditions generally, as in subsequent 

 periods, and even as now prevail. 



The most common genera of the calrifcrous sandrock are Orthis and Strophomcna, both 

 being abundant among the lower layers. They arc the genera which figure so largely in the 

 oldest fossiliferous system, ninning up to the old rcdsandstonc. Some of the common fossils 

 are given in the annexed figure ; and though among the oldest inhabitants of tlie globe, they 

 resemble some of the common species of our own period ; and should they be presented to 

 any pala;ontologist ignorant of the position which they occupy, he would place them in or 

 above the carboniferous system. We find, therefore, that general form and modern look can- 

 not be trusted in deciding the age or era of fossils. In these older rocks, I have little doubt 

 hut a careful search will bring out a much greater number of species ; and this I am war- 

 ranted in saying, from the presence of many fragments of fossil bodies with those which are 

 already discovered. 



M. 



1. Scalitcs ani^iilatus. 

 '2. Machirca labtalus. 



3. Macitiroii strialus. 



4. Hellenipliun sulcatinus 



r>. Orlhis (n. s.) 

 6. Orl'icula (n. s.) 



The strata forming the calciferous sandrock at Ciiazy possess each a few characters worthy 

 of a moment's attention. The first and lowest stratum furnishes the usual characters of this 

 rock in other places, namely, the same mixture of siliceous, calcareous and other earthy 

 materials, interspersed with distinct sparry masses : these are among the most constant cha- 

 racters which the rock reveals. Wiiere the fossils begin to appear, they are small and obscure : 



