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REPORT ON THE DRIFT DEPOSITS AT MYTHOLMROYD. 
BY ROBERT LAAV, F.d.S., AND W.M. SIMPSON, F.G.S. 
On the south side of the river Calder, at Mytholmroyd, is 
a plateau or terrace raised some 20 to 50 feet above the 
present banks of the river, from which it is separated by a 
narrow tract of alluvial holm land. This terrace is about half 
a mile long, by 300 to 400 yards wide, and is on the 330 to 
360 feet Datum level. 
It is bounded on the west by Stubbs Clough and Hawks 
Clough, and on the east it extends to within about 100 yards 
of the Cragg Brook, near its junction with the Calder, whilst 
on the south it abuts against and is bounded by the rising 
valley sides. 
Although the Cragg Vale Brook has almost evidently cut 
through and worn back the eastern edge of this terrace, the 
stream is now seen running against a cliff of grit shales on 
its east bank, and there is no evidence of drift deposits on 
that side. 
To the casual observer this terrace has the appearance of 
a well-defined alluvial river terrace only. 
For many years, however, local geologists have known that 
the deposits forming the terrace contained more than the ordinary 
river alluvium and local rocks, and it appears somewhat strange 
that the Memoirs of tlie Geological Survey of the Burnley Coal 
Field, which include this district, make no allusion to the dis- 
covery of erratics here. 
Although these Memoirs were published so late as a.d. 1874, 
the authors say in reference to this area, " The only part of 
this district in which drift lias been observed is the northern 
liank of Boulsworth." " 
* Sec (icology of the lUu iilcy L'oalticld, p. 120. 
K 
