434 PROFESSOR GEIKIE ON THE |! 
liers, and extends from the flanks of Finlay Seat, past Elgin and Forres, ascend- 
ing the Findhorn to Sluie, and then curving round the northern slopes of the 
Lethen hills, until it crosses the lower reaches of the Nairn, beyond which it 
skirts the shore for a few miles, until lost under raised beaches and blown sand. — 
Thus the area of Upper Old Red Sandstone, by coming directly against the | 
crystalline rocks to the south of Elgin and in the Findhorn, separates the lower 
or Caithness flag division of the system into at least four tracts. Of 
these one extends from Buckie up the valley of the Spey, between the 
slopes of the Rafford hills and the tongue of Upper Old Red Sandstone, 
which protrudes up the valley of the Findhorn. A second smaller tract of 
the lower division appears at Altyre; while on the west side of that tongue 
a third area rises into the heights of Lethen Bar and Clune, and extends 
up the valley of the Muckle Burn. To the west of the hills of Rait and 
Urchany the lower division is found interposed between the upper sand- 
stones and the crystalline rocks, and gradually swelling out westwards, until 
on the Drummossie Muir it fills the whole space between the base of the hills 
and the sea. 
It is only when this structure of the ground is made out, that we can under- 
stand the differences in the character of the strata which lie next to the gneiss 
and granite, even in sections at short distances from each other. We must also 
bear in mind the irregular indented character of the ancient coast, as well as 
the uneven and, indeed, rugged slopes on which the conglomerates and sand- 
stones were deposited. Thick masses of conglomerate are apt to die out 
rapidly, and to appear on different horizons, so that we cannot always safely 
identify two conglomerate bands, even though they both rest upon a common 
platform of the crystalline rocks, and may not be more than two or three 
miles apart. 
Beginning, then, at the eastern extremity of the Old Red Sandstone belt of 
Moray and Banff, we find at Buckie an admirable shore section, showing the 
unconformable position of this system on the crystalline rocks below. The 
quartz-rocks and quartzose flags, with partings of garnetiferous mica-schist, 
which occupy the shore between this point and where we left the conglomerate 
at Portknockie, here once more pass under a coarse red breccia, with a cal- 
careous matrix. But unlike the massive deposit of Gamrie and Aberdour, the 
breccia is only 20 or 30 feet thick, and is immediately succeeded on the west 
side of the harbour by thin purplish-red and grey flagstones, with bands of coarse, 
somewhat brecciated conglomerate. In these strata Dr Matcotmson found 
fish plates and scales, as at the Tynet section, to be immediately noticed. At | 
the west end of the village of Buckie additional proof is afforded of the uneven 
denuded surface on which the Old Red Sandstone was laid down. A small 
knob of the underlying strata projects from among the sandstones, of which, | 

