240 NOTES ON THE I'EKMIAN SYSTEM OF 



Brachiopoda are limited to tlie lower portions of the series — to 

 the Marl-slate, Compact-Limestone, and Shell-Limestone. There 

 is no authenticated instance of the occurrence of a Brachiopod in 

 the breccia or above it. The greatest number of Gasteropods 

 are found in the middle division, the Shell-Limestone. Four 

 species of Couchifera appear to be common to the whole lime- 

 stone series — viz., Myoconcha costata, Brown; Axinus dubius, 

 Schloth. ; Myalina Ilausmanni, Goldf. ; and Leda speluncariiiy 

 Gein. 



The ^\'orks principally referred to in the following Table were 

 published at the time mentioned below — viz., 



Gelnitz. "Die Verstelnerungen,'' April, 1848. 



HoAvse. " Trans. Tyneside N. F. C, vol. i." Aug. 17th, 1848. 



King. "A Cat. of Org. Rem.," Aug. 19th, 1848. 



King. '' Moil. Perm. Foss.," 1850. 



