136 REPORT—1883. 
Eleventh Report of the Committee, consisting of Professors J. 
Prestwich, W. Boyp Dawkins, T. McK. HuGues, and T. G. 
Bonney, Dr. H. W. Crosskry, Dr. DEANE, and Messrs. C. E. 
De Rance, H. G. ForpHam, J..E.. LEE, D.. MACKINTOSH, W. 
PENGELLY, J. PLant, and R. H. Tippeman, for the purpose of 
recording the position, height above the sea, lithological charac- 
ters, size, and origin of the Erratic Blocks of England, Wales, 
and Ireland, reporting other matters of interest connected with 
the same, and taking measures for their preservation. Drawn 
up by Dr. Crosskey, Secretary. 
THE Committee is able to record many additional facts respecting erratic 
blocks, in its report for the present year. ‘The Committee continue to 
confine their work to recording the observations made, and do not 
attempt to offer theoretical explanations. The information collected 
will enable the distribution of the erratic blocks to be mapped with con- 
siderable accuracy, and it is ultimately intended to tabulate the results 
obtained. 
This work, however, must necessarily be delayed in consequence of 
the constant discovery of fresh groups of erratic blocks. 
So many new facts are reported to the Committee year by year from 
different parts of the country, that it would lead to mistaken generalisa- 
tions to make any attempt at complete classification. 
Yorkshire.-—The Committee have received from Mr. James E. Westby, 
of Sheffield, the subjoined report on erratic blocks found at Crosspool :— 
Crosspool is about one and a half miles west of Sheffield, on the 
rising ground to the left of the Sheffield and Glossop turnpike road, and 
lies on shales underlying the Middle Rock (Gannister Series) of the 
Lower Coal Measures. 
To the east the ground slopes towards Sheffield; to the west it begins 
to slope to the. Rivelin Valley. To the north-east the Middle Rock 
sandstone forms a bold escarpment ; while the land from Crosspool rises 
quickly to the south-west up to Sandygate. 
The heights of the various points above sea-level are: Lydgate, 
800 ft.; River Rivelin, 350 ft.; Crosspool, 730 ft.; Sandygate, 850 ft. 
To the west of a line drawn from Sandygate, through Crosspool to 
Lydgate, the drainage and fall is towards the River Rivelin, while on 
the eastern side of the same line the rainfall is ultimately drained into 
the River Porter, both of which streams are tributaries of the River Don. 
Lying on the high land forming the outer edge of the drainage area of 
the River Porter, on its north side, there is a triangular patch of flat 
ground, now very uneven, having been worked for brick-making, over 
which lie scattered blocks and boulders of various sizes, which have been 
exposed and left in their present position by the workmen, who have 
generally got all the available clay. 
In the sections exposed the clay containing these blocks varies from 
2 ft. down to 10 and 12 ft. in depth, differing much from the ordinary 
surface-clays of the district, which are generally the decomposed coal- 
measure shales. 
