339 
THE YORKSHIRE BOULDER COMMITTEE 
AND ITS NINTH YEAR’S WORK. 
THOMAS TATE, F.G.S., 
Leeds, Hon. Secretary to the Committee. 
Durinc the year our knowledge of the glacial deposits in the 
Calder Valley has been extended. Mr. Burton, Horbury, reported 
the cutting of a trench 26 ft. deep across the valley in connection 
with the drainage works at Mirfield. The proportion of erratics was 
greater than at Horbury (reported 1893), and small mountain 
limestone boulders were present, though not so plentifully as were 
observed at Savile Town. At both localities where these have been 
noted they were usually decomposed for half an inch or so from 
the surface. Mr. Thomas Saltonstall has found numerous small 
unstriated pebbles between Sowerby and Luddendenfoot at altitudes 
ranging from 500 to 800 ft. above the sea. Possibly these may be 
the remnants of earlier deposits than those we are now considering. 
But the most instructive excavation is one still going on at Millwood, 
Todmorden, 600 ft. above sea-level, reported by Mr. Robert Law, 
F.GS., an active member of this Committee. It is interesting as 
being the most westerly exposure of boulder clay as yet observed in 
this valley. It has therefore been visited from time to time by other 
members of this Committee. The foreign rocks are, without excep- 
tion, the same as were reported in 1893 from localities lower down 
the valley, the different kinds holding the same relative proportions 
as at Horbury—Buttermere granophyre, Eskdale granites, Borrowdale 
andesites, Old rhyolites, and Yewdale breccia. As regards the 
Calder Valley, we may now note—(1) The erratics are, on the 
average, larger at Millwood and decrease in size as we descend the 
valley. (2) They are highly polished, and many retain their fine 
glacial strize at this station; as we descend they lose their striz and 
become more water-worn. (3) The mountain limestone boulders 
are best preserved at Millwood ; they decrease in number, are more 
and more decomposed, and finally disappear in the lower reaches of 
the valley. (4) The rocks which characterise the Irish Sea glacier 
on the one hand, and the Tees glacier on the other, are conspicuous 
by their absence from the Calder Valley. (5) All the foreign rocks 
observed in this valley may have been brought from the Lakeland 
area south of a line drawn from Workington to Coniston, the ice- 
tongue bearing these being deflected eastward by lateral pressure of 
Dec. 1895. 
