1869.] MACKINTOSH LITHOD0M0T7S PEEFORATIONS. 281 



Mr. Mackintosh believed that a minute study of the actual effects 

 of rain and other atmospheric agents would convince any one that 

 these perforations were not the result of weathering. " The pits, 

 holes, or crevices produced by chemical decomposition, or the slight 

 mechanical action of rain-drops *, are either rough or present no 

 regularity of outline, and they always conform to the varying com- 

 position and structure of the rock. The distinction between the 

 perforations under notice and all other indentations in limestone 

 rocks is obvious." In one large specimen Mr. Mackintosh noticed 

 that the perforations were more circular, smooth, and cleanly cut 

 than a hole made by an iron borer, which happened to be in the same 

 slab of rock. " They all present a uniformity of pattern irrespec- 

 tively of the character of the rock. They generally occur in groups, 

 which often ramify from a large shallow entrance or lobby. In 

 most cases the mouths of the holes would appear to have been either 

 fractured off by frost or in some other way destroyed ; but instances 

 have been found in which they have been preserved, and then the 

 mouths are seen to be smaller than the interior of the holes. They 

 frequently exhibit circular striae, as if excavated by a rotating, or 

 partially rotating, agency. The perforations have been ground out 

 by some cause as evidently as any rock-surface has been subjected 



to a grinding process They are associated with smoothly 



hollowed, rounded, and funnelled rock-surfaces which run under the 

 drifts of the limestone districts of N'orth-west Lancashire." 



In conclusion, the author expressed his belief that the holes were 

 ground out by some animal while the land was submerged, either 

 before, during, or after the Glacial period. 



P.S. Very lately (July 1869) I have found numerous similar per- 

 forations at altitudes between 1000 and 1400 feet above the sea, near 

 Buxton, the most perfectly preserved (about seven-eighths of an 

 inch in diameter, and often 3| inches long) occurring on the steep 

 or south-west side of Hill-head Yalley, about a mile S.E. of Parks 

 Inn.— D. M. 



Discussion. 



Mr, GwYN Jeferets remarked that Mr. A. Tylor had already 

 called attention to the same subject three years ago. He could not 

 agree in regarding the perforations as made by any moILusk or other 

 animal. The borings of Pholas, Saccicava, and Gastrochcena were not 

 parallel, but enlarged towards the base into a pear-shaped form. 

 They were also comparatively straight, and not curved or bifur- 

 cated as in the limestones exhibited. The range in height was also 

 against their being the work of marine mollusks. He thought the 

 perforations were more probably due to atmospheric agency. 



Prof. Ansted had seen in the large blocks of the Cyclopean walls of 



* " The holes generally open downwards, or horizontally, on the protected 

 sides of projecting ledges or blocks, in situations to which rain has Httle or no 



access." 



