The Wiltshire archaeological and natural history magazine . e shall see that thebeds by Chiseldon have a slope, or dip as it is called, to thesouth, and that this south dip continues till you pass Marlborough,where the direction of the dip changes and the beds are also bentup so that at Savernake they dip north, while at Graf ton they againdip south. Below the level of the line *—* the beds have been continuedbelow the surface of the ground to show their order underground,and the effect of the uprise, forming the Pewsey Yale. The beds in our cutting fall into three classes, clays, sands, andli
The Wiltshire archaeological and natural history magazine . e shall see that thebeds by Chiseldon have a slope, or dip as it is called, to thesouth, and that this south dip continues till you pass Marlborough,where the direction of the dip changes and the beds are also bentup so that at Savernake they dip north, while at Graf ton they againdip south. Below the level of the line *—* the beds have been continuedbelow the surface of the ground to show their order underground,and the effect of the uprise, forming the Pewsey Yale. The beds in our cutting fall into three classes, clays, sands, andlimestones, represented by the gault, the upper greensand, and thechalk. There is a gradual passage from the gault clay to the uppergreensand, the clay growing more sandy till it becomes a true sand,and again there is a passage from the greensand to the chalk, theformer becoming more and more calcareous till it passes into chalk. IBut in the lower part of the lower chalk are some verysandy and gritty beds, the middle chalk differs from the upper •SOil i. xo ? zo I o s HX m o oxmr~~vin m> z o o X m Omo 5 O o>r > g > o > om H o m Omoroo? I o Ox mro o oo orr z oCO oc3 m Chiseldon to Collingboume, 93 chalk, and both these divisions of the chalk have thin hard bedsand seams of marl, all of which have their due significance. The distribution of the fossils in the chalk and the consequentestablishment of zo)ies, or bands, in which similar assemblies offossils occur, and of stages, have received much patient investigationat the hands of Dr. Barrois and Messrs. Jukes-Browne, Hill, andothers, and the history of the chalk—once thought to be so simple—is found to be a complicated one. We will now commence our journey along the line, startingfrom Swindon, though this is outside the limits of our diagram. The old town of Swindon stands on high ground, a capping ofPortland sand and limestone, on clay. The old houses avoided theclay and kept to the sandy beds, for water wa
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
