Scientific Intelligence. 77 



existing stream capable of so introducing it. No bones or other re- 

 mains were found in it. 



Dr. Buckland also explained tbe occurrence of such sand, &c. by 

 diluvial action, and proceeded to remark a curious circumstance con- 

 nected with these caverns. There has never been an instance in 

 which any deposits have taken place at the bottoms of caves, except 

 such as are composed of recent remains, and the mud, sand, &c. of 

 the surface; debris and fossil remains of older formations never occur 

 in them. The only instance known of any older remains in caverns, 

 is that of the caves at Palermo, belonging to the later tertiary period, 

 and containing shells, &c. of that formation perforated by pholades, 

 though now raised 300 feet above the sea. 



Dr. Buckland also observed that the origin of caves in limestone 

 had during many years occupied his attention, and has always been 

 considered by him one of the most difficult problems in geology. To 

 a certain degree they have in many cases been the effects of mechani- 

 cal violence producing lateral movements, and tearing asunder portions 

 of solid rocks, during the elevation, or subsidence, of the strata in 

 which they occur. In cases of this kind, the fractures are usually 

 rectilinear, and partake of the nature of a slip or fault, never filled 

 up. But the lateral enlargements and tubular communications that 

 proceed in various directions from the main apertures, and the vaulted 

 and dome-shaped expansions that occur at irregular intervals along 

 the minor winding passages, cannot be referred to mechanical vio- 

 lence ; and an adequate cause of their origin may possibly be found 

 in the influence of acid vapours, (probably carbonic acid,) rising 

 through fractures adjacent to these corroded portions of the limestone. 



Caverns in solid limestone could not have been produced, like cells 

 and cavities of various size in beds of porous lava, by air included in 

 the viscid substance of the strata, before or during the progress of con- 

 solidation, because they are most abundant in limestones of the most 

 compact character, and in which no other trace of cellular structure 

 is to be found. Moreover, the interior of caverns usually presents an 

 irregular carious surface, similar to that which is produced on a mass 

 of limestone submitted to the action of an acid. 



If these supposed acids were mixed with water, the lime thus dis- 

 solved would have been removed in a state of solution, and the sides 

 of the caves would be found studded with the less soluble contents of 

 the strata, such as siliceous concretions, and fragments of organic re- 

 mains, standing in relief, as we often see them around the interior 

 of these carious vaultings. 



The organic remains in these strata, particularly the corals, are 

 often disposed in such a manner as to shew that considerable time 

 elapsed during the deposition of the successive beds of limestone in 

 which they are enveloped ; no accumulations of gas in connected 

 cavernous expansions passing from one stratum into another could 

 have taken place in beds of limestone thus deposited at successive 

 intervals. 



Dr. Daubeny expressed a doubt as to whether all caverns could be 

 accounted for by aqueous corrosion alone, and conceived that the 

 large vaulted chambers into which many of them suddenly expand, 



