NATURAL HISTORY SOCIETY OF GLASGOW. 329 



Stirling to Ardrossan. Good sections of these rocks are to be 

 seen in the several glens that traverse these hills in the Campsie, 

 Strathblane, and Fintry districts, as well as in the valley of the 

 Leven, and amongst the hills above Greenock, in the district 

 around Loch Thorn; but the only organisms yet found in any of 

 these localities are a few plant remains, and fragmentary scales 

 of fishes, both of which, however, are very rare. The tract of 

 country from which the specimens under notice were obtained 

 lies beyond the range of bedded traps referred to, and it is very 

 probable that this fossiliferous group of the calciferous series is of 

 newer age than that which underlies the trap of the hills. The 

 shales are of a dark-grey colour, and are more or less arenaceous 

 in their composition. They resemble very closely in this respect 

 those found in the calciferous series of Fifeshire, which also 

 contains similar groups of fossils. The following are the 

 organisms which Mr Young had been able to identify — sphenoid 

 bone of fish resembling that of Ctenodus, scales of a fish like those 

 of Rhizodus, or Strepsodus, small tooth of fish, bivalve shells like 

 those of Anthracomya or Modiola, impressions of the limb of a 

 crustacean, entomostraca of various species with the valves often 

 crushed. Amongst these he had found Beyrichia suharcuata, 

 Leperditia Scotohurdigalensis, and a large species of Cythere. 

 Spirorbis carbonarius is seen attached to the shells, and a layer of 

 the shale is almost composed of the crushed shells of Spirorbis 

 helideres. In washing a portion of the shale containing this 

 annelide he had noticed the interesting fact that in many of the 

 specimens where the tube was filled with calcite, these tubes 

 when broken across showed that they were often traversed by 

 thin septa of a concave form like those seen in cephalopod shells, 

 but not perforated with a siphuncle, as in these shells. These 

 septa appear to occur in the tubes at irregular distances, one 

 specimen showing two septa at about a line apart. This septate 

 character had not, so far as he was aware, been noticed in 

 connection with this annelide before, and he could find no 

 specimens or descriptions of tubicolar annelides, recent or fossil, 

 in which similar septa were found, although it was probable such 

 did occur.* Spirorbis helideres is found abundantly in one of the 

 musselband ironstones in the upper coal measures of Lanarkshire, 



* Since this date Mr Young has discovered concave septa in two specimens 

 of recent Serpula in the Hunterian Museum. 



