1870.] SHARP NORTHAMPTONSHIRE OOLITES. 373
and, in the aggregate, fall short by 3 feet of the measured depth of
the well.
A quarter of a mile north of this point, and a mile and three quarters from Duston " Old" pit, in my own garden, at a lower level than y, the limestone bed overlying the slate bed (no. 5, a and b, of " Old " Duston) occurs ; and below, but not immediately, is found cellular ironstone with ochreous cores.
At a mile S.E. of Hopping Hill, and at a little more than a mile west of Northampton, in the angle formed by the junction of the roads to Weedon and Duston, is perhaps the most important ironstone quarry in Northamptonshire. During the last eleven years the excavations, varying in depth from 25 to 35 feet, have been extended over an area of about 16 acres. (See z.)
The whole section belongs to my division E, and consists of iron-stone of varying richness. I have noted the section some five times at various intervals, but have found no very great variation in the character and order of the different beds ; and in this respect they offer a striking contrast to the D beds of Mr. Bass's pit, the variation in which is so remarkable.
These beds are very fertile in organic remains ; and, through the intelligent and watchful assiduity of Mr. Eldret, the overlooker of the works, I have been enabled to obtain from this quarry a large collection of fossils, upon the significance and importance of which it is needless, and would be out of place, for me to dilate. I have often paid my thanks to Mr. Eldret ; and I think the thanks of geologists generally are due to him, but for whose active interest in the preservation of these fossils they would certainly have been consigned to the smelting-furnace, and thus lost to geological science.
A great part of the area of excavation was the site of a Roman burial-ground ; and, through the agency of the same Mr. Eldret, I have obtained many interesting Roman and Romano-British antiquities, with which the surface-soil and underlying disturbed material abounded.
The surface-soil is generally about three feet in thickness, but, from ancient disturbance, is frequently mixed up with the material of the upper bed of the ironstone — this disturbance having penetrated to irregular depths, frequently of 6 feet.
The following are the particulars of a recently exposed section : —
Section of Ironstone at Duston Quarry.
ft. in.
1 . Surface soil and rubbly ironstone, mixed by disturbance and very irregular, with zone of Cardium cognatum or Buckmani at bottom 6 0
2. Stratified cellular ironstone with ochreous cores, in thin layers 3 0
3. Ironstone, more sandy and very shelly, with large Nautilus (obesus), Ammonites Murchionoe and A. corrugatus, Pholadomya fidicula, Cardia, &c 3 0
4. Rich cellular ironstone with sandy cores — zone of Astarte elegans, Trigonioe, Ceromyoe, and many other shells 1 0
5. Bed in blocks of sandstone, oxidized upon joint and bedding planes 1 0
6. Very rich cellular ironstone, containing many corals : from this bed
