130 Proceedings of the British Association, 



Caput- Serpentis, which lives even at the present day. This Fauna, 

 which did not appear until after the deposition of a considerable bed 

 of mottled clays containing no traces of animal life, commences 

 similarly to the Fauna of the two cretaceous periods by a series of 

 clays containing numerous peculiar myaciform shells, and their 

 associated Pectunculi and Ostracese. The earliest fossiliferous bed at 

 WhiteclifTe Bay is a most remarkable thin stratum, almost entirely 

 composed of a species of shell-bearing annelid, the Ditrupa (Denta- 

 lium planum of the Mineral Conchology), which appears to have lived 

 but a short time and suddenly disappeared. In the midst of these 

 strata beds charged with myriads of foraminifera, probably indicating 

 some change in the sea's depth, appear and cease. The sudden con- 

 version of the sea into a fresh-water lake, indicated by a stra- 

 tum of Paludina clay, its return into a brackish state, and the 

 consequent re-appearance of certain marine animals, its reconversion 

 into a fresh- water lake thronged with myriads of fluviatile mollusca, 

 and the almost momentary influx of salt water during that period, 

 lasting only so long as to enable a race of oysters to live and die 

 away, all render the tertiary strata in this locality highly interesting. 

 From the great zoological break between the eocene and the chalk, 

 the authors conclude that a third or uppermost cretaceous formation, 

 characterized by a Fauna which would link the middle term of that 

 system with the middle term of the tertiary, has disappeared in this 

 locality, whilst they regard the cretaceous system there present, as 

 composed of two divisions, equivalent in time, the older consisting 

 of the lower greensand, and the upper or later composed of gault, 

 upper greensand, and chalks, considered as one system. 



Mr. Oldham reported the progess of the ' Observations on Sub- 

 terranean Temperature in Ireland, undertaken at the request of the 

 Association. — In July 1843 thermometers were placed at the copper 

 mines of Knockmatson Company, Waterford, which are worked to 

 the depth of 774 feet. Of the four instruments employed, one 

 was hung in the open air four feet from the surface ; one hung freely 

 in the gallery at the depth of 774 feet ; one in the rock at the same 

 depth ; and one in the lode or metallic vein. The rock is indurated 

 clay-slate, the ore massive copper pyrites in quartz veinstone. The 



