4 Dr. T. G. Halle — Equisetites Stems 



of sand tliat accumulated on the spot. On the other hand, it has 

 been argued that the upright position need not be primarj^ ; it 

 might be as readily explained if the stems are regarded as 

 drifted and secondarily deposited on the spots where they are 

 now found. It is well known and has been pointed out, 

 particularly in the discussions of the upright stems in the 

 Coal-measures, that a drifting ti'ee often has a tendency to sink in 

 a vertical position, the root-end being heavier because of adhering 

 mineral matter or IVom some other reason. Phillips describes, in his 

 Oeology of the Yorkshire Coast, a locality at High Whitby where 

 upright stems of Eq^uisetites columnaris occur in the sandstone. He 

 continues': "They . . . are broken off or imperfect above, and 

 seldom reach to the upper surface of the bed ; they are also broken 

 off below, but commonly pass to the lower surface ; and some of the 

 lower joints nearest the roots are found in the subjacent bed of shale." 

 These facts have led, according to Phillips, to the conjecture that 

 the plants grew in the sliale " and were buried by an influx of sand 

 and water ". The other possibility, that the stems had been floating 

 and deposited in vertical position, was at one time contemplated by 

 Phillips, but he finally became convinced that "in several cases on 

 the coast . . . -£'2't«sei!« were prostrated and buried in abundance near 

 to the spots where they formerly grew, and that here and there a few 

 stems appear erect in the attitude of their marshy growth ". 



It would appear as if the idea of a preservation in situ of the 

 upright Equisetites stems had been, in later years, discarded for the 

 opposite one. Seward, who figures in his Fossil Plants a fine 

 example of three upright stems in one piece of sandstone, expresses 

 himself in the same work decidedly for the drift hypothesis.^ The 

 question does not appear to have received much attention lately, but 

 it certainly deserves to be more studied both from a palseobotanical 

 point of view and yet more because of its bearing on the mode of 

 deposition of the sandstone. Many instances of occurrence of upright 

 Equisetites stems have been noted by different geologists. It is not 

 intended to give any review of the previous observations here ; but 

 the subject will be more fully treated by Professor P. Kendall in 

 a paper following the present. 



During a visit to the Yorkshire coast, in the summer 1910, for the 

 purpose of collecting fossil plants, I paid, on the initiative of Professor 

 A. G. Nathorst, some attentinn to the upright stems of Equisetites 

 cohimnaris. The species is a very common one, and occurs in both the 

 shales and the sandstones of tlie Lower and Middle Estuarine Series. 

 In the shales the plant is mostly found as impressions or as very 

 flattened casts lying on the bedding-planes. In the sandstones, on the 

 other hand, it commonly occurs as upright cylindrical casts covered 

 with a thin dark coating which often exhibits the teeth and other 

 features of the leaf-sheaths. The vertical stems appear to be especially 

 common in the sandstone cliffs of the Lower Estuarine Series along 

 the coast from Whitby to Haybnrn Wyke, but they are found also in 



' J. Phillips, Illustratioiis to the Geology of Yorkshire, pt. i, The Yorkshire 

 Coast, 3rd ed., p. 143, London, 1875. 



- A. C. Seward, Fossil Plants, vol. i, p. 72, 1897. 



