Note on the Well-Section at Rock Mills and the Fauna associated with Edestus

Abstract

The well at Rock Mills (Messrs. Joseph Sykes & Co.) is situated in the mill-grounds in the valley of the River Hohne at Brockholes, about 4 miles south of Huddersfield. According to the Geologiqal Survey-map (Quarter-Sheet 88 S.E.), the alluvimn in the valley at this point rests on shales which underlie the Rough Rock, the uppermost member of the Millstone Grit. The shales appear to vary considerably in thickness in this district. Green states that 100 feet of shales are present between the Rough Rock and Grit A about Holmfirth, which lies 2 miles south of Brockholes; while on Holestone Moor, west of Huddersfield, he estimates that thev are 200 feet thick between the same horizons. Spencer has shown that in the district embraced in the next sheet to the north (Quarter-Sheet 88 N.E.) the shales contain a marine fauna; and the discovery of Edestus should stimulate the efforts of the local geologists to further work on this horizon. During the excavation of the well no record of the various strata passed through was made by the sinkers; but it appears, from notes supplied by Mr. J. R. Simpson, of Banks, Honley, that the rocks were mainly shales, with some thin beds of sandstone. At the depth of 120 feet the specimen of Edestus was obtained by Mr. H. H. Freer in a bed of rock—rather friable shale,—which also contained numerous fragments of marine shells. Among the specimens the following have been identified:— Posidoniella lœvis (Brown), Gastrioceras sp., Glyphioceras reticulatum (Phill.)