Notice of a striated boulder lately found in Tynecastle Sandpit, Edinburgh
David Milne Home · Transactions of the Edinburgh Geological Society · 1874
The boulder is of basalt, and was estimated to weigh nearly three tons. The annexed lithographed sketch BCD may help to indicate its shape. The sides are well rounded, especially the sides CB and CD. The greatest length is 4½ feet, greatest width, 4 feet; thickness about 2 feet. The two angles or corners most rounded are C and D. The upper surface of the boulder, before being disturbed, sloped N.W. by N. (magnetic), at an angle of about 20°. The longest diameter, viz., from C to a point halfway between B and D, bore N.E. by E. The side CD bore N. by E.; the side DB, E.S.E.; the side CB, E. by N. The upper surface of the boulder presented three or four strongly-marked striae bearing N. 60° E. as shown on the figure. But besides these, there were a few striae more minute, running obliquely. These, also, are shown on the figure. Besides striae on the upper surface, there were one or two strongly marked on each side, radiating from the angle C. The idea suggested by these was, that the agent or agents which made the striae, when moving over the surface, came on the edge and were pressed along these sides, for these striae dip towards the east, as if the striating agent slided downwards by force of gravitation. At the suggestion of Messrs Stevenson, C.E., the boulder was turned over, in order to see if there were any markings on the under surface, and