Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/546

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.

seams of marly clays, together with Terebratula maxillata, T. intermedia, and Clypei, adds greatly to the resemblance. I should be inclined, therefore, to assign them to the Forest Marble of East Gloucestershire and North Wiltshire. — J. Lycett."

Dr. Lycett has authorized me also to say that he considers the ironstone beds of the Northampton Sand equivalent to the ferruginous beds of Glaizedale and " the Doggers," Yorkshire, but that he has not found sufficient evidence for identifying any part of them with the " supra-Liassic " sands of the Cotswold district. — S. Sharp.]

Fig. 5. — Diagram of General Section, showing the position of the Inferior Oolite Limestone and Divisions of Northampton Sand.

Northampton Sand Upper Middle Lower

Blisworth Clay (2 ft.)

White Limestone (25 ft.)

Blue Clay (15 ft.)

Ferruginous band

Place of Great Limestone of the Inferior Oolite

White Sand (12 ft.)

Plant-bed

Variable beds (30 ft.)

Limestone slate (4 ft.)

Beds containing ironstone (35 ft.)

Amm.-bifrons bed


Great Oolite. Line of unconformity. Inferior Oolite.


Conclusion. I have thus endeavoured, however imperfectly, to illustrate the Oolitic geology of a portion of the county of Northampton, and have left ample material for further inquiry.

Although the ground I have travelled over yields so much that is worthy of interest, an extension by a few miles of the field of investigation would bring other beds and other questions under review, which would amply repay for time and labour bestowed upon their examination.

By including the Blisworth area in my present Memoir, I have added a member to my General Section in the Great-Oolite Clay which overlies the limestone in the Blisworth quarry, and which, I believe, was first detected as distinct from the overlying Glacial Clay many years ago by Professor Morris.