1862.] HARKI^ESS PTERASPIS-BEDS, 255 



sected by the streams flowing into the Allan, affords exhibitions of 

 the rocks of this area. 



On Sherra Muir, at Blackford of Burn Ogilvie, the grey beds 

 are wrought, and have the 'N.W. dip at 20°. The same beds are 

 seen on the east side of Sherra Muir, in the course of the Millstone- 

 burn which joins the Allan near Greenloaning Station ; and in this 

 stream we have the sequence of the grey and purple beds well shown. 

 At Balhardie in the brook-course the higher purple strata occur, and 

 are worked; they are flaggy, and have green layers and nodules 

 accompanying them. The rocks here are false-bedded, but the pre- 

 vailing dip is N.W. at 20°. This locality is on the road from 

 Greenloaning to Dunblane ; and to the S.W. thereof we have, in the 

 stream on the road from Dunblane to Kinbuck, the same purple 

 flaggy strata, with the same dip and direction ; and these false -bedded 

 sandstones have been partially worked about a mile and a half N.E. of 

 Dunblane, on the east side of the road. 



North-west of the Bridge of Allan. — In the country which lies 

 west of the Allan we have strata of a like nature manifested ; but 

 in passing north-westward into the area drained by the Teith, we 

 have other and higher strata exposed than those which the Allan 

 Water exhibits. West from the Bridge of Allan, along the escarp- 

 ment in the north side of the Carse of Leckrop, the grey sandstones 

 are seen ; west of this, at Craig Arnhall, these are succeeded by the 

 purple portion of the series, and in the upper parts of these latter 

 intercalated light-purple shales occur. On the north side of the 

 Teith, in Craig Arnhall Wood, the light-purple shales are exclusively 

 seen, and these continue to the Farm of Eow. The whole of this 

 series of strata, as seen west of the Bridge of Allan, has the N.W. 

 dip at an angle of about 20^. In passing higher up the Teith these 

 purple shales have interstratified with them thin beds of fine-grained, 

 brown- coloured sandstones, which gradually increase until we find 

 the higher strata entirely composed of the latter. This is the case 

 at Ardoch Bum, which flows past Doune Castle ; and of these brown 

 sandstones this stronghold is built. As seen in the stream at Doune 

 Castle, the brown sandstones have in them green laminae, and are 

 spotted with the same colour ; here their dip is W. at 20°. The 

 brown sandstones are also seen above Doune, in the course of the Teith 

 at Deanstown, and about half a mile to the W.W.W. they have been 

 worked. Above Doune Bridge they exhibit N.W. inclinations. 

 Beyond Deanstown, in the course of the Teith, they are seen in the 

 grounds of Lanrick Castle stiU with a N.W. dip, but at a low angle ; 

 and they continue, as seen in the Teith, all through the estate of 

 Lanrick, becoming to the W.N.W. by degrees almost flat. They 

 pass gradually upwards into grey flaggy rocks which, within about 

 four miles of Callander, have become nearly horizontal. 



In the course of the Teith, from about four miles below Callander 

 to this place, no rocks are seen in the river ; at Callander on the 

 Muir, which is situated on the south side of the river, conglomerates 

 make their appearance, made up for the most part of quartz-frag- 

 ments. These conglomerates, which are well developed, and which 



VOL. XVIII. PABT I. s 



