Percy F. Kendall — Glacial Geology. 497 



but to be looked for to be found in profusion, and in the second case 

 (Whalley)/ where "obscure shell fragments" were recorded, a very 

 short search sufficed to find foreign stones in the very same pit, and 

 boulders, large and small, of Scottish and Cumbrian rocks were in 

 evidence in many places in the neighbourhood. It is an exceptional 

 thing to find any considerable deposit of Drift in the course of the 

 great Irish Sea glacier, which is destitute of shells or shell fragments. 



These are the positive facts of distribution. Now I would 

 dwell a little on the negative evidence. I am duly mindful of 

 the treacherous nature of negative evidence, but when able and 

 industrious observers in all parts of the country have been assiduously 

 searching for half a centurj^ or more, and have not brought forward 

 one contradictory fact, I shall scarcely be accused of rashness if I 

 lay some stress upon this failure. 



If our country had been submerged to a depth of 1350 feet, it is 

 surely not too much to ask why there are no shell-beds in the 

 secluded mountain valleys in the great hill-clusters. 



The fewness of the exposures, a reason assigned by Mr. Eeade, 

 cannot be taken as a very satisfactory explanation. If there are not 

 so many gravel-pits or brickfields there are more mines and quarries, 

 and the streams cut deeper and show cleaner sections ; but, after all, 

 it is not solely a question of shells, there should be beaches and 

 cliffs, but where are they ? 



When we consider, again, the condition of the shells what do we 

 find ? The shells are comminuted and pounded in such a fashion 

 that one may work for hours even in some of the most prolific beds 

 and not find a perfect shell of any sort, and, astounding fact, in the 

 20,000 square miles or so of recently elevated sea-bottom in Lanca- 

 shire, Cheshire, and the Drift-covered areas to the south, a bivalve 

 with the valves in apposition has never been found, unless we admit 

 as exceptions Mr. Nicholson's Gault Inoceramiis and the Saxicava 

 found in a bored boulder. 



It might, too, be pointed out that we have no record of a single 

 stone or shell being found encrusted with barnacles, and of the two 

 bored stones recorded from the Boulder-clay of the area in questioJi 

 one was distinctly glaciated,^ and the other, which formed the subject 

 of a paper by Mr. Shone, had the crypts filled, not with the sur- 

 rounding Boulder-clay, but with a fine sand very rich in microzoa, 

 which is without its like amongst the Drift deposits of the district. 

 Ml'. Shone was led by this fortunate find to investigate the contents 

 of univalves, and discovered that many of those found in the Boulder- 

 clay contained a similar rich sand. He offered an explanation, which 

 however ingenious, still fails to account for the total absence of any 

 similar deposit on a larger scale. Scratched shell fragments are 

 fairly common, and it is worthy of note that sub-perfect univalves 

 are much more common than bivalves in equally good condition. 

 The relative perfection of shells at high- and at low-levels respec- 

 tively has been stated in the following very misleading terms (Geol. 



1 See Geol. Surv. Memoir of the country round Burnley. 



2 "Nature," vol. xl. p. 246. 



DECADE III. — VOL. IX. — NO. XI. 32 



