348 EEroET— 1879. 



of fossils, especially the fish remains of Lantivet Bay and other districts, and con- 

 tended that they partook more of the character of Upper Silurian than of Devonian, 

 and showed that the stratigraphic evidence supported this conclusion. 



He then showed that these rocks rested upon Lower Silurian rocks, which, how- 

 ever, covered a very much more extensive area than was shown on the official 

 maps. 



He also stated that still older rocks, of at present indeterminate age, came up 

 from beneath the Lower Silurians at several points on the coast, and especially on 

 the north, between Newquay and Perranporth, and suggested that the mica-schists 

 •of the Lizard were probably of the same age as these last-mentioned beds. 



In conclusion, he drew attention to the vast periods of time indicated by the 

 successive changes in direction of the folds in the strata, and to the vast amount of 

 metamorphism to which all the rocks had been subjected. He also suggested that 

 the rarity of fossils in many of the older beds might be due to the existence of a 

 highly-minerahsed condition of the waters through which the sediments fell, and 

 which would cause those sediments to be charged with mineral matter. The sub- 

 sequent segregation of these substances into later-formed fissures would account for 

 the abundance and richness of the Cornish mineral lodes. 



6. The Surface Bocks of Syria (suggested by the Quarries at Baalbek). 

 By James Perkt, B.E., County Surveyor, Boscommon. 



The country of Syria, where there are vast areas of irregular bare limestone rock, 

 with alternations of heat and rains, and where the radiation into a clear sky at 

 night is considerable, gives evidence of the action of a geological agent not taken 

 much account of by persons who five in and visit countries where the hard rocks 

 are mostly covered with a considerable thickness of soil, gravel, or clay. 



I visited in the neighbourhood of Beyrout some quarries of a peculiar kind of 

 sandstone. Beyrout is situated on a limestone coast, but to the south of the town 

 there is a shifting field of sand which extends itself in varying directions as the 

 prevailing winds vary, and it at the present time threatens to bury a considerable 

 portion of the town, gradually advancing over a few additional houses each year. 

 The sandstone in question is formed by a mixture of particles of limestone from the 

 coast and the sand I have spoken of, which drifts and consolidates layer by layer 

 into a series of low hillocks ; these are one connected mass, and the mass is in- 

 creasing in an evident manner under existing circumstances, although it is cut into 

 caves and passages by quarrying the stone for building purposes. The stone is un- 

 equal in composition and appearance ; in some places there is more carbonate of 

 lime than in others ; in parts the fantastical appearances of drifted snow are shown 

 in miniature ; and in many places the stone looks like rigid sponge. The mass is 

 made solid by the action of rain water which dissolves the particles of carbonate of 

 calcium, and, on being slightly elevated in temperature, re-deposits the carbonate 

 of lime so as to cement together the particles of sand. It is this function of lime- 

 stone in solution, affected by change of temperature distinct from mere evaporation 

 (a cause usually supposed to effect more than I think it is capable of effecting), to 

 which I wish to direct attention. 



I have been at least a mile inside a stalactitic cavern whose floor was a river or 

 lake, the atmosphere was continuously saturated, and if there be evaporation it is 

 very slight indeed, where the stalactites were of huge proportions. The idea that 

 these stalactites are formed when water which has filtered through hundreds of 

 feet of limestone reaches an atmosphere slightly higher in temperature than the 

 rocks, appears to me the correct one, although the rotten incrustations on the 

 intrados of masonry bridges may be accounted for principally by evaporation. 



I have repeatedly come to the assistance of housekeepers in limestone districts, 

 by recommending a little hydrochloric acid to remove the deposit of limestone in 

 glass bottles where water is kept for drinking purposes, and this is clearly a case of 

 the kind of deposition in question. 



