HARDWICKE'S SCIENCE-GOSSIP. 



251 



report said " they spak guid Ebrew," a result not 

 more remarkable than if the verdict had been " guid 

 Lowland Scotch." 



The geology of the island is extremely interesting 

 and is highly illustrative of that of the shores of Fife 

 as seen at Pettycur, about two and a half miles to the 

 north, of which probably the Inchkeith series is an 

 outlier. It affords a very fine opportunity for the 

 study of intrusive trap-rock and the accompanying 

 deposits of calciferous sandstone and carboniferous 

 shale. The first impression conveyed to the mind 

 when the general mass is viewed from a distance is 

 that it must have been the apex or plug of an extinct 

 volcano, but a closer and fuller examination of the 

 stratified rock soon dispels that idea. The trap 

 {whinstone) is a greenstone or dolerite, composed of 

 the minerals grey felspar and augite in very fine 

 grains, and this rock comprises fully five-sixths of the 

 entire island rising in the northern portion to a height 

 of one hundred and eighty feet above sea-level. 

 This trap would appear first to have fractured and 

 displaced the sandstones and shales, and later to have 

 protected them from the destructive influence of the 

 sea by acting as a natural breakwater. The sedimen- 

 .tary beds have undergone a considerable amount of 

 •change, due to their contact with the igneous rock. 

 Thus we find the shale converted into a hard, brittle 

 rock which breaks almost like slate, while the sand- 

 istones are variously affected, here presenting a quartz- 

 'like appearance, there a burnt limestone effect is 

 produced, and nowhere is it found where it has not 

 been in a greater or lesser degree altered from its 

 original texture, colour, and hardness. It is quite 

 noticeable too, that in the proximity of its junction 

 with the sedimentary rocks, the trap (or whinstone) 

 loses its crystalline appearance and becomes of a red 

 and earthy nature. In the southern part of the island 

 many of the amygdaloidal cavities are filled with 

 -crystals of carbonate of lime, chalcedony, and silica, 

 and these when water-worn have a very pretty 

 ■effect, resembling some of the porphyries found in 

 Perthshire. The dip of the intrusive trap and the 

 stratified rock is to the north-east, the average being 

 about 45°. 



Having regard to the vast amount of heat evolved 

 by the igneous rock when first poured forth, and the 

 resulting changes in the strata, it of course follows 

 that very few remains of past life reward the efforts 

 of the geologist. As may naturally be expected, this 

 extreme heat has all but obliterated them, and little 

 or nothing is to be met with except the almost 

 microscopical tests of the Ostracod crustacean 

 Leperditia subrecta which occur fairly abundantly 

 in the shale. Maclaren in his " Geology of Fife and 

 the Lothians," suggests that the carboniferous lime- 

 stone crops out in the bed of the Forth a little to the 

 east of Inchkeith, but the persistent absence of 

 limestone pebbles on the east shore tends somewhat 

 to throw doubt on this supposition. Still, when we 



take into consideration the steep declivity of the 

 rocks at this part, the great depth of the water and the 

 direction of the currents, we have quite sufficient 

 grounds for not accepting the absence of carboni- 

 ferous limestone pebbles as conclusive evidence that 

 the carboniferous limestone formation is wanting. 



In the north-east of the island there is to be seen 

 one of those curious memorials of prehistoric 

 times known to archasologists as Kjokken-Moddings 

 (Anglice, Kitchen Middens) or shell-mounds. These 

 are simply the refuse heaps upon which were thrown 

 the shells and bones of the various creatures which 

 were used as food by the primitive people who 

 formed them. The example at Inchkeith, first 

 brought into notice in 1872, may almost be considered 

 as a typical one, and is well seen in a section made 

 by the cutting of a military road leading to the 

 North Battery. The entire exposure has a depth of 

 a little over eight feet, consisting at the base of a 

 fairly compact and dark-coloured rubble. Upon this 

 is the mound made up of tens of thousands of cast- 

 away shells of Patella vulgata, Biicciimm undatum. 

 Purpura lapillus, and Littorina littorea, together 

 with a large number of bones, chiefly from the 

 porpoise {Delphimis phcccwnd), and seal {Phoca sp.). 

 Some of these bones have been split to enable the 

 operator the more readily to extract the marrow, 

 while many of them show traces of having been in 

 contact with fire. The mound is in its turn covered 

 by a loose rubble, varying in depth from twelve to 

 sixteen inches, and consisting of sand and decayed 

 vegetation. If this upper rubble were removed the 

 shell-heap would be found to be in the shape of an 

 irregular ring, with a diameter of from thirty to 

 thirty-five feet and with a maximum depth of 

 eighteen inches, " thinning " out as it gradually 

 approaches the margin. Within or very close to this 

 ring was reared the dwelling of the mound-makers, 

 a dwelling situated on high ground, to which the sea 

 although near was inaccessible. Unfortunately it is 

 impossible to give even an approximate dale to the 

 period when these rude inhabitants lived, and the 

 language they spoke, the customs they observed, and 

 the conditions under which they existed are all lost 

 to the pages of unwritten history. They were most 

 probably a migratory people, wandering from place 

 to place, living in exposed situations in summer and 

 seeking shelter on the approach of winter. No 

 weapons or utensils have yet been discovered at 

 Inchkeith, but from those obtained in Denmark, 

 where they have been very extensively found and 

 studied by Professors Steenstrup and Worsaae, 

 it has been inferred that they were made during 

 the early Stone Period, and that they were quite 

 probably of the same age as the earliest lake dwell- 

 ings. It must however be mentioned that Sir 

 John Lubbock records {" Pre-historic Times," 4th 

 edition, page 234) the finding of a large bronze 

 pin in the large shell-mound of Loch Spynie, 



