3°2
ON THE GEOLOGY AND PAL~ONTOLOGY OF FORFARSHIRE. By GEORGE HICKLING, D.Sc., F.G.S. HE Old Red Sandstone of Forfarshire was recently described T in the Geological Magazine (1908, Hickling), and as the account there given is readily accessible we may here endeavour principally to supplement it.
TECTONIC STRUCTURE. The Highland Boundary Fault is the master feature govern ing the rocks of the district. In the centre of Forfarshire the throw of this fault cannot be much less than 10,000 ft. The folding of the rocks is strictly parallel with the fault; alongside of it the rocks form a deep syncline, of which the northern limb is steep, the southern more gently inclined. To the south-east the rocks roll over again, forming a symmetrical anticline, of which the Sidlaw and Ochill hills are the denuded remnant. In addition to this principal folding there is a much slighter warping about axes, which run N.W. and S.E. Two anticlines of this series affect the area under consideration-one, of very slight effect. has an axis running across the syncline north of Forfar j the second axis lies wholly under the sea, but is doubtless not far east of Stonehaven. This fold was much more pronounced and is responsible for bringing the base of the Old Red to the surface in Kincardine. Apart from the highland fault, there is no evidence of any faulting of structural importance. The admirable coast sections reveal large numbers of such fractures, but they are mostly small and tend to counteract one another.
THE LOWER OLD RED SANDSTONE. In the paper to which allusion has been made the following provisional subdivision of the Old Red, based on the local litho logical facies, was suggested: It. Edzeil shales .. 1,000 Arbroath sandstone 1,200 Auchmithie conglomerate 800 Red Head Series . 1,50 0 Cairnconnan Series 2,000 Carmylie Series . 1,000 Dunnottar Conglomerate 5,000 Stonehaven Beds . 1,50 0
14,000 THE GEOLOGY AND PALlEONTOLOGY OF FORFARSHIRE. 303
It was shown that only the Cairnconnan and Carmylie series are definitely fixed in age by palreontological evidence. More recently, Dr. Campbell has announced the discovery of Down townian fossils in the Stonehaven beds (191 I, Campbell), which must therefore be transferred to the Silurian system, leaving the Dunnottar conglomerate as the base of the Old Red. Restricted as above, the Old Red Sandstone may be described as consisting of a great basal conglomerate succeeded by a series of sandstones, flagstones, and shales. In southern Forfarshire the only notable conglomerates above the Dunnottar group are those which resulted from the denudation of the volcanic cones which were piled up during the deposition of the overlying rocks. There is one noteworthy exception to this, viz., the Auchmithie conglomerate, near Arbroath. In this, the pebbles are mainly quartzite, are beautifully rounded, and occasionally reach 12 inches in diameter. It would seem to imply that "highland" rocks were still exposed within reason able distance, notwithstanding the fact that 10,000 ft. of Old Red sediments had already accumulated, in addition to the Silurians. The whole of the Old Red deposits become much coarser in character as the highland border is approached. This is well illustrated by the contrast in the character of the Cairn connan series on the two sides of the Sidlaw anticline. In its southern outcrop, between Arhroath and Carmy lie, it is essentially a series of grits and sandstones, with only insignificant con glomerates. To the north, as at Turin Hill, coarse conglomerate is largely developed in it. I suspect that these conglomerates were mistaken by Powrie for the Dunnottar series, and so led him to believe that the fish-bed of Turin Hill was on the same horizon as those of Canterland Den and Farnell, and to assume the presence of a large fault north of the anticline, for which no evidence seems to exist (186 I, Powrie). Along the highland border the great fault cuts out a steadily increasing amount of the Old Red from Stonehaven, where its base is exposed, to the North Esk, where all below the Auchmithie series appears to be thrown below the surface. In this region only the bright red Edzell shales are free from conglomerate. There is a peculiarity of colouring which deserves attention In the lower portion of the system the sandstones are usually dull red or grey, the shales red or blue, and the colour in all cases very even. Towards the top of the series, red becomes almost completely dominant and much brighter in hue, while a curious mottling makes its appearance. This is most con spicuous in the Edzell shales, which are frequently mottled with small circular patches of yellow, grey, or green, or more rarely have bands of the same colours. The same feature is well hown in the sandstones near Kelly Castle; Arbroath. GEORGE HICKLING ON
UPPER OLD RED SANDSTONE. It was shown in my former paper that the small remaming outliers of Upper Old Red between Perth and Dundee, at Arbroath, at Boddin Point, at Montrose and at St. Cyrus are remnants of a nearly horizontal sheet, which must originally have extended along with the Carboniferous rocks, whose base it forms, over the Sidlaws and probably as far as the highland border. It is needless to describe these deposits again, beyond a state ment that they present a basement conglomerate overlain by soft light red and mottled sandstones and cornstones. The relations of the Upper Old Red show clearly that the Sidlaw anticline and Strathmore syncline had been completely formed, and that denudation had reduced the arch to pretty near its present surface level, before the Upper Old Red and Carboniferous were spread over the old land-surface and buried the ancient Sidlaws. This Carboniferous sheet is the last deposit which there is any reason to suppose has ever spread over Forfarshire, and it appears to have played the principal part in determining the present topography. During the general "sagging" of the Central Valley in Permo-Carboniferous times the sheet would doubtless acquire a gentle south-east slope, and give rise to a series of consequent rivers flowing over Perthshire and Forfarshire in that direction. During subsequent denudation the hard ridge of the Sidlaws gradually emerged again and seems to have proved a powerful check to the rivers crossing it. The Earn, however, crossing the barrier where it was broken by faulting, and being thereby greatly favoured, was able through its tributaries to capture successively the head-waters of the Almond, the Tay, the Ericht and the Isla, building up the complex stream which now flows along Strathmore.
PAL£ONTOLOGY OF THE LOWER OLD RED OF FORFARSHIRE. The fauna of these rocks is of the highest interest, alike to the geologist and paleeontologist ; which makes all the more remarkable the fact that it has received scarcely any attention since Powrie ceased collecting about 1870' No complete list of the fossils has to my knowledge been published. Much more unfortunately, no adequate record exists of the exact localities from which fossils were obtained, and it is highly improbable that anyone can now supply it. An effort has therefore been made, in the table now given, to collect such information as can be found scattered through various papers. A complete list of the sources of information will be found in the bibliography at the end of this paper. It may here be noted that the most important accounts of the fauna are those of Mitchell (r861), THE GEOLOGY AND PAL-EONTOL OGY OF FORFARSHlRE. 305
Powrie (1864), and Powrie (1870). We may note at once, also, that almost the whole of the fossil localiti es are situate within narrow stratigraphical limits, in the Carmylie and Cairnconnan series. Notes on Beds and Localities.-Powrie latterly concluded that all the fish-remains came from a single bed, of which he speaks as follows (Powrie (1864), p. 414): "This bed is composed of ~ semi-calcareous shale, some bands highly calcareous and serm crystalline, and having many embedded nodul es. A peculiar band of a tenacious light-coloured clay, some 5 or 6 inches in thick ness, is very persistent in this shale, and from it the Fish-bed may be recogni sed wherever it crop s out. The colour of these calcar eous shales varies much. . . . The thi ckness varies from 3 to 8 ft. Some of the layers are exceedin gly fissile, splitting into larnime not much thicker than writing-paper. I have now found this Fish-bed in Canterland Den in Kincard ine shire, near Farnell, at Turin Hill, in some quarries south of Forfar, in many places, in the Sidlaws, in Balruddery Den in Forfarshire and in R ossie Den in Perthshire." It seems scarcely possible that this can be true of Turin Hill; it may be correct regarding the other localities named, the bed being just at the base of the Cairnconnan series. Most of the localities named in the table are rath er vague. Balruddery Den is 5 miles N.W. of Dundee. T ealing is 5 miles north of Dundee, on the western margin of a basalt sill. Th e Myreton quarries are 1 mile east of the same sill. Pitairlie probably refers to exposures on the Pitairlie burn , 3 miles north of Monifieth, It is on nearly the sam e horizon as the Kelly Den exposure, near Arbroath, in the Red Head series, and much higher than any of the others. In Kelly Den the exposure is immediately above the grounds of Kelly Castle. The Forfar quarries are about a mile south of that town. Pitscandly is half a mile N.W. of Clocksbriggs Station. Turin Hill appears to include a number of localities. In one place it is referred to as "on the east flank " of the hill ; in another, as " on the north side." The former no doubt refers to the Tillywhand land quarries. The hill is 3 7~ miles KN.K of Forfar, Carsegownie is on the Hill of Findhaven, 176 miles N.W. of Turin Hill. The fossiliferous quarries at Leysmill adjoin the station. Those of Carmylie are at the terminus of the Arbroath and Carmylie railway. The Farnell exposure was made in the banks of the Pow burn, 3/z mile south-west of Farnell Station. Canterland Den (Den of Morphie) is 4% miles N. of Montrose. Goodchild (19°4, p. 597) refers to a "Myriapod Bed " yielding Kampecaris and Archidesmus, "near the base of the Strathmore sandstones and close to the top bed of the main part of the volcanic rocks." This would indicate the Kelly Den hori zon, but no locality is given, and I have found no other record. He also refers (p. 598) to "Auchtertyre, near 3° 6 GEORGE HI CKLING ON Newtyle,' probably the same localit y recorded elsewhere as " New tyle." Geikie ( 1897, p. 301) records the discovery of fish remains by Mit chell at Ferryden, Montrose. T his horizon is a little lower than th at of Carrnylie , So far as can be judged in th e ab sence of a detailed survey th e localities are in th e following stratigraphical order : (5 ) Kelly Den, P itairlie, " Myriapod Bed " (Goodchild). (4) Carsego wnie, Brechin. (3) P itscandly, Turin Hill. (z ) Newtyle, Glammis, Forfar, Reswallie, Montreathmont Muir, Farnell, Canterland Den. (1) Balruddery, T ealin g, Myret on, Carmylie, Leysmill, Ferryde n.
C OAST SECTI ON S. Between Arbroath and Lunan Bay the upper members of the Old Red series are exposed in a manner which it would be difficult to surpass eith er for clea rness of sections or beauty of coast. Leaving th e east ern side of Arbroath we emerge on "Victoria Park," a fine exa mple of th e z5 ft. raised beac h, 13i mile in length, and 3i mile in maximum width, backed by steep slopes 50 to 70 ft. in height. About 3i mile east of the old Salt Pa n, the natural bo undary between the Arbroath sands to nes and the U pper Old Red may be tra ced ac ross the foreshore. T he Park is term inated eastwards by th e" Ness " (" Wh iting N ess " of th e maps), th e first point of th e cliffs which stretch northwards for seven miles. At th e Ness th e un conform ity betwee n th e Low er and U pper Old R ed can be seen with beautiful clearness by walking roun d the base of the cliff, a no table point being th e term ination eastward of th e horizontal beds of the U pper series against an old cliff of the Lower sands tones. F or the next mile-and-a-half the cliffs are deeply serra ted with numerous sea-gullies, all having doubtless originated as caves, of which man y still remain. The influ ence of master-joints on marine erosion is very clearly exhibited. In th e "Mermaids' K irk " we have a large blowhole with the peculiarity that the cave by which it opens to th e sea run s parallel to the general coast-lin e. At the entrance to Dickmont's De n is a small blowhole which may be seen in act ion during south-east gales, the water spouting to 140 ft. above sea-level. A little farther, the De'il' s H ead is a fine stack which must obviously have been formed when the land was at a lower level. Its interest is increased by the fact that the master-joint by which it was cut off is continued through th e spur of cliff immediately to the south, from which a precisely similar sta ck is in course of formation (the " Three Storey House "). From the Ness to the point now reached the coast has been THE LOWER OLD RED SANDSTONE OF FORFARSHIRE.
T .-\RLE OF FOSSILS AN D LO CALITIES-GEORGE HICKLING, D.Sc ., F .G5 .
-e
MEROSTOMATA . P terygotus anglicus, A I[...... X X ... X X ... X ... X ... X X ... X· X .. , ...... Pterygotus min or, H . Woodward ...... , ...... , X '" ." I...... Eurypterus brewsteri, H . Woodward .. . I ...... , ... " ...... , X .., Eurypterus pygm reus, Salter ...... , .., .., .., tylon uru s powriei, Page ...... s ...... , . ... X ... .., .., ...... Stylonurus scoticus, H . Woodward , ...... " X ...... , ...... , .., .. . .. , Stylonurus ensiformi s, H. Woodward...... " ...... X .., ......
MYRIAPOD A. I Kampe caris forfaren sis, Pag» ." ...... X ...... X ...... " X ." X ...... , .., I Archidesmus macnicoli, Peach ...... X ...... " ... .. , .., ... .. , I . I ! PLANTJE. I, Parka decipien s, Floning ... X X X X X X X " X X X X ...... I X ... X ...... I Pachytheca, sp., HOORO' (1) ...... " ., . .., i .., .. , .., ... I ...... I ...... I Zosterophyllum myreton ianum, Penhallow X " , X ...... i ... X ...... X ...... " ...... Psilophyton, sp , Dt/wson .. , ...... , ...... , .., ...... , , I.., Arthrostigma , sp...... i '" ...... " ...... i , , , , Cycl opteris, sp (?) ...... " ... ." ... .. ~' :I ...... I ! I - I I J I • Goodchild (Igo l) ; no other recor d. i C. W. Pe ach (, 879). t Occu rre nce re ported t o Egerton by Mitchell. § Speci men in Dundee Mu seum . II Goodchild (1904), .. Au cht er tyre, near Neweyle."
TO FACE PAGE 306. THE GEOLOGY AND PAL~ONTOLOGY OF FORFARSHIRE. 307 following the strike of the Arbroath sandstones, which are here rather coarse and pebbly, with a steady dip of from 20 degs. to 25 degs. south-east. We now turn into Carlingheugh Bay, a broad opening caused by the emergence of the relatively soft Upper Old Red. The rocks of the Upper series may very well be studied at this spot. They are seen to consist of highly irregular alternations of conglomerates with soft false-bedded sandstones, light-red in colour with occasional yellow mottling. Their contained pebbles present a wonderful variety of "high land" rocks, with the sandstones and lavas of the Lower Old Red. The southern boundary is an unexposed fault; the bed ding, here as elsewhere, is practically horizontal. A series of horizontal rock-ledges (the" Floors") form a broken platform extending about 300 yards out to sea. They are just covered at high water, and clearly represent a raised platform of denudation belonging to the period of the raised beaches, one of which lies behind the bay. Crossing the bay, we find the northern boundary of the Upper Old Red also faulted, the fault being beautifully exposed in a small promontory, where its throw is about 180 ft. The sea has attacked this line of weakness and drilled a hole (the" Dark Cave") completely through the head land. About 20 yards south of the cave the fault line is displaced westwards by a "wrench" to the extent of some 80 yards. Passing through the Dark Cave we find the fault on the farther side of the promontory occupied by a vein of barytes 2 yards in diameter. Here also we see again the base of the Upper Old Red resting unconformably against a steep bank of the Arbroath sandstone. The line of the cliff onward to Lud Castle is remarkably straight, being determined through the greater part of that interval by the fault just mentioned. The gap in the cliff on the south side of Lud Castle shows a section of an isolated patch of Upper Old Red, which here fills a V-shaped valley in the Arbroath sandstone, at least 100 ft. in depth. In the field some IS0 yards north-west of this is the" Gaylet Pot," a blowhole 100 yards long by 50 wide and 140 ft. deep, communicating with the sea by a cave 100 yards in length. We now reach the base of the Arbroath sandstones in Castlesea Bay, north of Lud Castle, where they pass down into the Auchmithie conglomerates already noticed. The several massive conglomerates and sandstones of this series form the broken cliffs northward by Auchmithie to Maw Skelly. Two hundred feet beneath the lowest thick conglomerate at this point is a single conglomerate band 15ft. thick. This band is tossed about in quite a remarkable fashion between Maw Skelly and Rumness by a series of considerable faults, which, but for its presence, would probably pass unnoticed. The lowest of the massive conglomerates, just mentioned, 308 GEORGE HICKLING O~ may co nveniently be taken as the base of the Auchmith ie series. We are now therefore in th e Red H ead series, which occ upies th e coast from Maw Skelly to Lun an Bay. Its upper portion is coarse sandstone, occa sionally pebbly. As we descend, the general facies becom es finer, to hard red shale and shal y sand stone between Prail Cas tle and the R ed H ead. At th e latter point we reach the top of the int er-bedded volcanic series, which will be described sepa rately. Meanwhile we may pass on to L unan Bay to note the magnificent raised beach there displayed, with its seaward barricade of sand-dunes, which at R ed Cas tle have ponded back the mouth of the Lunan Water and compelled it to make a co nside rable de tou r. The sands of th e bay un fortunately hide th e outcrop of the Cairnconnan series, while th e Carmylie series which form s th e cliffs to the north is repr esent ed solely by its lavas. Boddin Point, the northern end of the bay, presents an interesting outlier of Upper Old Red resting on th e lavas of the Carmylie series, which was fully described in my form er paper. V OLCANIC ROCK S. The volcanic rocks of eastern F orfarshire, together with their extensions in Kincardine, constitute what Sir A. Geikie has described as the "Montrose" group of eruptions. (Ge ikie, 1897, vol. I, p. 299)' The principal ce ntres of eruption probably lay to the south-east of Mo ntrose, while th e exposed lavas thin away along their outcrops in bo th directions from that town. As Dr. Campbell has recently shown (Ca mpbell, 1911), volcanic activity began already in Silurian tim es. The climax of th e eruptions was reached during the deposition of the Carmylie series, while the last of the lavas are inter-bedded in the lower portion of the R ed H ead series. At the Red H ead , south of Lunan Bay, the highest of th e several serie s of lavas is beauti fully expose d. F ollowing the coast from south to north we cross the rocks in descending orde r as follows: fl . Fine red sha ly sa ndstone. ( 12) Coarse volcanic cong lomera te with sub-ang ular and ro unded hlocks up to I ya rd diameter, and matrix of volcan ic material 50 (II) Coarse ashy sa nds ton e i ([0 ) Congl ome rate •.. 10 (9) F ine asby sandstone. 1 (8) Conglomerate, with sandy mat rix 5 (7) Fine micaceous ashy sandstone, up to 1 (6) Fine sandy conglomerate. 3 (5) Fine flaggy and sha Jy sandst one • 10 (4) Coarse conglomerate with sa ndy matrix 10 (3) Coarse volcanic sandstone and breccia 3 (2) Hard red shale • . . . 2 (I) Volcanic conglo merate with sandy matrix 10 +
l°S -i- THE GEOLOGY AND PALiEONTOLOGY OF FORFARSHIRE. 309
The above series of rocks occupies the shore between Cuthile Harbour (No. 12) and the base of the northern spur of the Red Head (No. I), a distance of 490 yards. The beds are enumerated in detail in order to bring out the remarkable manner in which they thin in a northerly direction, as may be seen in the cliff sections. In the northern spur of the Red Head the whole series of beds is reduced to about one-half the total thickness given above, the conglomerate No. 12 being scarcely distinguishable. Within the next 400 yards or so to the north of the Head all the conglomerates seem almost completely to die out, their constituent blocks also becoming smaller III the same direction. Underlying conglomerate No. I of the above series is a thickness of about 130 ft. of very fine red shaly sandstone before we reach the uppermost of the lavas. These sandstones contain subordinate bands of volcanic detritus, notably an irregular lenticular mass of very coarse breccia which makes its appearance in the cliff section 300 yards north of the Head, swelling suddenly to a thickness of 30 flo or more, and then dwindling gradually northward. The sandstones them selves take part in the general northerly attenuation. In the foregoing facts we seem to have a clear picture of a volcanic cone somewhere to the south of the Red Head, the lavas of which were demolished by the waves to form the rocks we have described. The lavas tbemselves are first encountered a little south of the ruins of St. Murdoch's Chapel. They are admirably laid out in plan on the foreshore and exposed in cliff section for upwards of a mile to the base of the series in Lunan Bay. At the latter point the top of the underlying sandstones may be observed at very low tide. The total thickness of the series must be about 600 ft. Attention is first arrested by the extremely confused nature of the volcanic pile. I have never observed at any point a thickness of more than 10 ft. of compact lava. The upper surface of each sheet is usually highly amygdaloidal, often a mere pile of scoriaceous blocks. Even the compact lavas are often rent by deep fissures. The irregular cavities in the slaggy beds and the fissures in the lavas are invariably filled with fine greenish sandstone, remarkably well laminated, and sometimes forming regular "sandstone dykes." These interstitial sand stones obviously represent the results of sedimentation between the successive lava flows. In some cases the lavas seem to have been broken up into true breccias before they were buried by the next eruption. There must be upwards of a score of successive flows, but the extremely confused character makes the tracing of them a matter of the utmost difficulty. This locality has been well described by Sir A. Geikie (1897, Geikie, vol. I, pp. 299-30 1). The description now given of the Red Head volcanic series. .3 10 GEORGE HICKLING ON may be applied with little modification to all the inter-bedded lavas of the Forfarshire Old Red. In each case we have the same series of lava flows, and usually the same overlying mass of volcanic conglomerates. It is noteworthy that greenish-grey flagstones are usually associated with the lavas. This feature is especially marked in the case of the main group of lavas in the Carmylie series, and suggests that these flagstones (the "Arbroath flags") may be largely derived from the volcanic materials. Many quarries have. been opened in the more compact lavas, which are largely used for road-metal under the local name of "scurdy." The large vesicles of the amygdaloidal layers have become filled with a great variety of minerals, especially with a rich assortment of agates. The most prolific localities are the" Blue Hole," on the coast at Usan, 2 miles south of Montrose, and the railway cutting at Craig, I mile south of the same town. From these places Heddle (1901) records the following minerals: Zeolitic Quartz, Cairngorm, Sard, Onyx, Agates (many varieties), Hremachates, Moss Agate, Mochas, Gothite, Calcite, Saponite, Celadonite, Satin-spar, Barytes, Natrolite, Pilolite, Analcime, Stilbite. Intrusive volcanics are extremely rare in Forfarshire, except in the south, indicating the almost complete freedom of the district from igneous activity later than that represented by the inter-bedded lavas. REFERENCES. 1818. FLEMING, REV. DR. J.-" On the Mineralogy of the Redhead in Angusshire." Mems, Wern. Nat. Hist, Soc., vol. ii, pt. 2, p. 339. 1844-5. "Monogr. d. Poissons fossiles du Vieux Gres Rouge," Neuchatel et Soleure, [855. ;\1ILLEW, H.-" On the Less-known Fossil Floras of Scotland," Rep. Brit, Assn., 1855, sects., p. 83· 1855. PAGE, D.-" On Pterygotus and the Pterygotus-beds of Great Britain." Rep. Brit. Assn; 1855, sects., p, 89. 1856. SALTER, J. vV.-" On the Great Pterygotus (Seraphim) of Scotland and other Species." Rep. Brit. Assn., 1856. sects., p. 75. [859. BEATTIE, W.-" Notice of a Bone-cave near Montrose." Rep. Bn"!. Assn., 1859, sects., p. 99. 1859. EGERTON, St« P. DE M. GRAY.-" Remarks on the Nomenclature of the Devonian Fishes." Q. y. G. S, vol. xvi, p. 119. 1859. HUXLEY, T. H., AND SALTER, J. W.-Mems. Geo!. Sur,'. "British Orzanic Remains, Monograph I. (PterygotusJ." 1859. MITCH~U., H.--" On New Fossils from the Lower Old Red Sand stone." Rep. Brit. Assn., 1859, sects., p. II6. 1860. EGERTON, SIR P. DE M. GRAY.-" Remarks on the Ichthyolites of Farnell Road." Rep. Brit. Assn., 1860, sects., p. 77. 1860. POWRIR, J._H Notice of a Fossiliferous Deposit near Farnell, in Forfarshire." R,p. Brit, Assn., 1860, sects., P: 89. 1861. HUXLEY, T. H., AND EGERTON, SIR P. DE M. GRAy.-Mems. GEO!. Surv. "British Organic Remains, Decade X." (Devonian Fishes.] 1861. MITCHELL, REV. H._H On the Position of the Beds of the Old Red Sandstone developed in the Counties of Forfar and Kincardine, Scotland." Quart. yourn. Geol. Soc., vol. xvii, p. 145. THE GIWLOGY AND PALiEONTOLOGY OF FORFARSHIRE. 3 II
1861. POWI{JE, J.-H On the Old Red Sandstone Rocks of Forfarshire." Quart. JOU1'11. Geol. Soc., vol, xvii, p. 534. 1864. ------.-" On the Fossiliferous Rocks of Forfarshire and their Contents." Quart. Journ. Geoi. Soc., vol. xx, p. 413. 1864. V\'OODWARD, H.-" Description of some New Palreozoic Crustacea." Geol, Mag., vol. i, p. Ig6. 1865. ------.-"On some New Species of Crustacea belonging to the order Eurypterida." Quart. Journ Geol. Soc., vol. xxi, p. 482. 1868. (a) POWRIE, J .-" On the Connection of the Lower, Middle and Upper Old Red Sandstones of Scotland." Tram. Edin, Geot, Soc., vol. i, p. I I 5. 1863. (h) -----.-,. On the working together of Igneous and Denuding Agencies in the Formation of Scenery." Trans. Edin, Geol, Soc., vol, i, p. 185. 1868 and I870.-POWRIE, J., AND LANKESTER, E. RAy._H Monogr, of the Fishes of the Old Red Sandstone of Britain." PI. I, Pal. Soc. 1870. POWR1E, J.-H On the Earliest known Vestiges of Vertebrate Life; being a Description of the Fish Remains of the Old Red Sand- stone of Forfarshire." Trans. Edin. Geol. Soc., vol. i, p. 284. 1879. PEACH, C. W._H Notes on the Fossil Plants found in the Old Red Sandstone of Shetland, Orkney, Caithness, Sntherland and Forfarshire." Trans. Edin. Geol. Soc., vol. iii, p. 148. 1882. PEACH, B. N._H On Some Fossil Myriapods from the Lower Old Red Sandstone of Forfarshire." Proc. Roy. Soc. Edin., vol. vii, p. 177. 18S8. TRAQUAIR, R. H.-" Notes on the Nomenclature of the Fishes of the Old Red Sandstone of Great Britain." Gee], Mag., dec. 3, vol. v, P·50 7· I8go. WOODWARD, A. S., AND SHERBORN, C. D.-" Catalogue of British Fossil \'ertebrata." London. 189I. \VOODWARD, A. S.-" Catalogue of Fossil Fishes in the British Museum (Nat. Hist.), Part l l." London. 1891. DAWSON,SIRJ. \V.,and PENHALLOW, PROF. D. P.-"Parka decipiens." Trans. Roy. Soc. Canada, vol. ix, sect. iv, p. 3. I8g6. MACNAIR, P., AND REID J .-" On the Physical Conditions under which the Old Red Sandstone of Scotland was deposited." Geol, Mag., dec. 4, vol. iii, p. 106. 18g5. REID, J., AND MACNAIR, P.-·' On the Genera Lycopodites and Psilophyton of the Old Red Sandstone Formation of Scotland." Trans, Geoi. Soc. Glasgow, vol. x, p. 323. 18g7. GEIKIE, SIR A.-" The Ancient Volcanoes of Great Britain" (vol. i). London. 18g8. REID, J., GRAHAM, W., AND MACNAIR, p.-HParka decipiens, its Origin, Affinities and Distribution." Trans. Geo!. Soc. Giasgow, vol. xi, p. 105. !898. TRAQUAIR, R. H._H Notes on Palseozoic Fishes: No.2." Ann. and Mag. N. H., ser, 7, vol. ii, p. 67. 1899. REID, J., AND MACNAIR, P.-" Psilophyton, Lycopodites, Zostero phyllum and Parka decipiens." Trans. Edin. Geoi. Soc., vol. vii, P·368. 1900. GEIKIE, SIR A._H The Geology of Central and Western Fife and Kinross." .Vem. Geoi. Sur», Scot. I gOI. HEDDLE, M. F.-" Mineralogy of Scotland." Edinhurglt. IgOr. HORNE, J.-" Recent Advances in Scottish Geology." (Pres. Addr., Sect. C., Brit. Ass.) Geoi. Max·, dec. 4, vol. viii, p. 452. Ig04. GOODCHILD, J. G.-" The Older Deutozoic Rocks of North Britain." Geo! Mag., dec. 5, vol. i, p. 59[, Ig08. HICKLING, G.-" The Old Red Sandstone of Forfarshire." Geo/, Mag., dec. 5, vol. v, p. 396. Igl 1. CAMPBELL, R.-" Preliminary Note on the Geology of S.E. Kincardineshire." Geol. ilfag., dec. 5, vol. viii, p. 63.