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A PRE=GLACIAL LAKE=BED NEAR NORTHALLERTON. 



EDWIN HAWKESWORTH, 



On a recent visit to Brompton, near Northallerton, a friend 

 drew my attention to a section exposed in making a pond in his 

 grounds. The surface was composed of a varjdng thickness of 

 Boulder Clay, containing numerous boulders of Carboniferous 

 limestones, sandstones and grits ; chert, grey and other granite, 

 and igneous rocks, including basalts, and one of Shap granite 

 quite a cubic foot in size. Beneath this Boulder Clay was a 

 bed of peat and peaty silt, in some places seven or eight feet 

 thick. Several small trunks, or branches of oak were found in 

 this. The peat rested upon about eighteen inches of white 

 marl, but, as the Avater had reached the top of this, and what 

 had been dug out had been dispersed, an examination of it 

 was impossible. However, I was informed that it was full of 

 shells, which, from the description given, would most likely 

 be some species of Limncea. 



My friend had laid aside, as a curiosity, a small mass of 

 quite green, compressed moss, which he had found between the 

 peat and the marl. I sent this to Mr. Wm. Ingham, B.A., who 

 identifies it as one of the Harpidioid Hypna — Hypnum ftuitans, 

 Linn., group exannulatum Renauld. var. pinnatum Boulay, 

 forma gracilescens Renauld. He writes that the same moss now 

 exists on shallow water splashes on Strensall and Skipwith 

 Commons, but the Brompton specimen differs from the modern 

 representative in being more pinnately branched, and in 

 hundreds of leaves floating off the moment its stem touches 

 water, due, no doubt, to its great age. The present plant 

 on the above commons is more rigid, and the leaves so firmly 

 fixed that they never come off when the stems are soaked in 

 water. The cell structure of the leaves is exactly the same 

 in both cases, as is the nerve. Mixed with this moss were a few- 

 stems of Hypnum cuspidatum, our commonest moss in wet 

 places. Notwithstanding its age, this is as rigid as its modern 

 representative, and does not lose its leaves when the stem 

 touches water. 



I secured a small quantity of shell-marl which was found 

 as a lenticle in the peat, and sent it to Mr. A. Gilligan, B.Sc, 

 F.G.S., who has examined it under the microscope, and reports 

 that it contains large numbers of Gyrogonites, the oospores 

 (or seeds), of the calcareous algae Chara. The spiral arrange- 

 ment of the whorls can'be seen on a number of perfect speci- 

 mens. Many of the internal cysts (or nuts, as the^^ are some- 

 times called), are present, both free from the surrounding 

 case of calcium carbonate, and some still inside it. These 

 show sharp spiral ridges. Planorhis is present in quantity, 



Naturalist, T 



