278 Notices of Memoirs — Horizon of Dithyrocaris. 



The Faunae Association of the Gallowhill Limestone. 



Thef auna of the Gallo whill Limestone is an exceedingly characteristic 

 one, and has a remarkable resemblance to that which exists on a much 

 higher stratigraphical horizon, the CalderwoodCementstone of the East 

 Kilbride district. So striking is the similarity between the two that 

 we here institute a comparison between them to show that they must 

 have been accumulated under closely similar physical conditions. 

 Both in the Calderwood Cementstone and the Gallowhill Limestone 

 the fossils are but sparingly distributed throughout the limestone, 

 and the rarer forms only occur at wide intervals. The following list 

 gives some of the principal species that occur in the Calderwood 

 Cementstone at such localities as Burnbrae, Jackton Burn, Kirkton- 

 holm, Glebe Quarry, and Limekilns House. 



Serpulites carbonarius, M'Coy. Lingula squaviiformis , Phill. 



S. membranaceus, M'Coy. Productus semireticulatus, Mart. 



Spirorbis caper atus, M'Coy. P. longispinus, Sow. 

 Dithyrocaris glabra, Woodw. & Eth. Bhynchonella pleurodon, Phill. 



D. granulata, Woodw. & Eth. Streptorhynchus crenistria, Phill. 



D. ovalis, Woodw. & Eth. Aviculopectenknockonniensis, M'Coy. 



D. testudinea, Scouler. Posidonoviya corrugata, Eth. 



D. tricomis, Scouler. Nuculana attenuata, Fleni. 



Palaimysis, Peach. Protoschizodus ceguilateralis, M'Coy. 



PalcBcrangon, Salter. Nucula gibbosa, Flem. 



Palcesquilla Pattoni, Peach. Sanguinolites plicatus, Portl. 



Anthrapalcemon Coutsii, Peach. Orthoceras attenuatum, Flem. 



Discina nitida, Phill. Nautilus sp. 



Serpulites carbonarius occurs in the Calderwood Cementstone, some 

 slabs being simply covered with the tubes of this worm. In the 

 Gallowhill Limestone they occur in exactly similar conditions. I have 

 also found traces of Serpulites membranaceus and Spirorbis caperatus in 

 the Gallowhill Limestone. 



The Phyllopod Crustacea from the Gallowhill Limestone include, 

 besides the two species Dithyrocaris tricomis and D. testudinea, others 

 whose specific characteristics have not yet been determined. Their 

 mode of occurrence and state of preservation are strongly suggestive 

 of the conditions under which these fossils appear in the Calderwood 

 Cementstone. No traces of the Schizopods which occur in the 

 Calderwood Cementstone have as yet been found in the Gallowhill 

 Limestone, but further search may yet reveal the presence of some of 

 these most interesting forms. 



The Brachiopod fauna of the Gallowhill Limestone is strikingly 

 similar to that of the Calderwood Cementstone. In the Carluke 

 district the Calderwood Cementstone is known as the Lingula Lime- 

 stone, because of the large numbers of that fossil which occur in it. 

 In the Gallowhill Limestone Lingula squamiformis is replaced by 

 Lingula mytiloides, which, as has already been pointed out, occurs in 

 great numbers. The more common Brachiopods in the Gallowhill 

 Limestone are Productus longispinus, P. semireticulatus, and 

 Rhynchonella pleurodon, and less commonly Piscina nitida and 

 Strep torhynchus crenis tria . 



Lamellibranchs are exceedingly scarce in the upper part or estuarine 

 phase of the Gallowhill Limestone, but several specimens referable 



