INTRODUCTION. 127 



Choenocaris ? Richf.eriana, sp. nov. Devonian, Saalfeld. 

 Hibbertia orbicularis, sp. nov. Burdiehouse, Scotland. 



Tail-pieces : 



Dithyrocaris lateralis, M'Coy. Mountain-limestone, Derbyshire. 



— — — Cement-stone group, Tweeden Burn. 



— Dunnii, sp. nov. Yoredale Beds, Redesdale. 



— Calciferous Sandstone group, Harelow Hill Quarry, 



Penton, Cannobie. 



— Neilsoni, sp. nov. Shales, East Kilbride. (See Note.) 



— sp. Calciferous Sandstone group, Leatwater, below Hirzel, 



Coldstream. 

 Gastric teeth (separate or in place) : Dolly Quarry and Cowden's Quarry, 

 Dunfermline ; Orchard Quarry, near Glasgow ; Hosie Limestone series, Campsie ; 

 Ardross, Fife ; East Kilbride ; Scaterau, Dunbar; Eccup, Yorkshire ; Congleton 

 Edge, Cheshire; Yoredale series, Redesdale; Newcastle-on-Tyne ; and Tyrone, 

 Ireland. 



The Calderwood Cement-stone (of the Lower Limestone group) is worked at 

 Calderside and East Kilbride, at the Kirktonholm and Glebe quarries and else- 

 where. It has there an average thickness of about two feet. It is regarded 

 as the equivalent of the First Kingshaw Limestone of the Lower Carboniferous 

 Limestone group of the Carluke district. The Cement-stone near East Kilbride 

 is succeeded in descending order by three limestones, locally known as Third, 

 Second, and First Calderwood Limestones, with their intervening and accom- 

 panying shales, certain of which have proved to be very fossiliferous, especially 

 that between the two lowest limestones (Nos. 2 and 1) of the section. 



The Cement-stone is known by other local names in the Carluke district, as at 

 Hallcraig Bridge on the left bank of Jock's Burn, where the Lingula-Limestone 

 and Shales of the Lower-Limestone series occur. There are also localities along 

 with the Raes Gill Ironstones, Carluke. 



For convenience of reference we give the following table of the Formations. 



Note. — The specimens marked "Shales, East Kilbride," in Mr. Neilson's and other collections, 

 are from shales in connection with the Calderwood Cement-stone. Nearly all are from the shale 

 lying over that limestone. Specimens of Dithyrocaris are very rare in the limestone and the shale 

 below, which differs considerably from the overlying shale. The exposures are only a few hundred 

 yards apart. It has been observed that, although the carapaces are well represented in this shale, 

 there are but few teeth found at East Kilbride ; and that where separate teeth occur carapaces seem 

 to be absent. Probably diverse currents may account for this fact. 



