138 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



also occurred : Eunicites curtus, H. ; (Enonites regidarisy 

 H. ; (E. naviformis, H. ; ffi". prceacutus, H. ; (E. 

 insignificus, H. ; CE. cuneatus var. humilis, H. ; CE. 

 as}ie7'sus, H. ; (E. tuberculatus, H. ; (E. chiroviovphus, 

 H. ; Arahellites extensus, H. ; A. spicaius, H. ; -4. 

 spicatus var. contractus, H. ; ,4. obtusus, H. ; ^. 

 aiigliciis, H. ; Statirocejjhalites serrula, H. ; and 

 Neridanus antiquus, H. Conodonts "were frequent 

 in connection with the Aymestry Limestone and 

 Ludlow Calcareous Mudstones, but rather rare in 

 the Wenlock shale. Minute pearls are found very 

 sparingly in the Wenlock shales, frequently in the 

 limestone, and commonly in the Aymestry shale. 

 Fossil pearls have been noticed by Professor Solas, 

 in the Quarterly Journal of the Geological Society, 

 vol. XXXV. (1879) ; by C. Barrois, in his Terrains 

 Anciens des Austuries et de la Galice (1882) ; by 

 Professor John Morris, in the Annals of Natural 

 History for August, 1851 ; one specimen from a 

 Jurassic ' Grypha'a, others from Kent Chalk, and I 

 have one from the Carboniferous shale of Brockley, 

 Lanarkshire. 



The Wenlock Limestone is generally of a greyish 

 colour, sometimes rather crystalline, and some of 

 the thinner beds are fine-grained. Ofte;n whole 

 posts are made iip of corals, and other beds are 

 almost entirely built up of encrinites. In some of the 

 quai'ries near Much Wenlock the dip is gentle, but 

 in the Ironbridge and Dudley districts very steep, 

 sometimes as much as 80°. There is a tendency in 

 some of the beds to assume a nodular structure. 



The Aymestry Limestone, taking it all over head, 

 is by no means such a pure carbonate as the Wen- 

 lock. Some parts of it are almost entirely made up 

 of the shells of the large bi'achiopod Pentamerus 

 Knightii. 



OSTRACODA. 



The Silurian Ostracoda are generally of a dark 

 greyish colour, some are earthy red, others have a 



