Table I. — Synopsis of the Cambrian Formation. _ [Quart. Journ. Geo!. Soc. vol. rix., to face page 44.' 



The order of succession in this Table is descending. — For further information see List of Authorities, pp. 37 & 38. 



1. Wales. 



From Menai Straits over Glyder Fawr 

 to the North of Snowdon. 



Prof. Bamsay, Horiz. Sect. 31, Geol. 

 Survey of Great Britain. 



2. England. 



Feet. 



a* Vi Z 



Slate 18 ° 



Grit 20 



Slate 400 



Slate and grit MO 



Grit and conglomerate 900 



Conglomerate and grit, obscure 1650 



5100 



Longmynd, Shropshire. 



Thickness probably not more than 



14,000 ft., as it is exaggerated by folds, 



the curves being cut off by denudation. 



W. T. Aveline, Horiz. Sect. 36 & 37, 

 Geol. Survey of Great Britain. 



Feet. 



Sandstone, coarse red 7,000 



Shale, sandy, red, micaceous... 300 



Sandstone and shale, hard, 1 AtjQQ 



coarse, red / 



Sandstone, hard, gritty, grey... 1,500 



Shale, purple, sandy 100 



Sandstone, coarse, reddish- "1 g nflO 



brown J 



Shale and sandstone, purple... 4,000 



Grey rock, very hard 1,000 



Conglomerate 200 



Sandstone, hard 400 



Shale, greyish-blue, slaty 2,000 



23,000 



No base seen. (No lime.) 



3. England. 



Longmynd, Sliropshire. 



4. Scotland. 



J. W. Salter, Quart. Journ. Geol. 

 Soc. vol. xii. p. 247. 



1. Sandstones and conglomerates, red. 



2. Slates and sandstones, grey, alter- 



nating. 



3. Sandstones, hard, grey, greenish. 



4. Slates and sandstones, grey and red, 



alternating. 



5. Slates, red, and hard. 



6. Sandstones, hard, greenish, very fine- 



grained, or micaceous, rippled. 



7. Schists, harder, rippled, felspathic ; 



thin shale, greenish, alternating. 



8. Schists, dark olive, with few lines 



of crystalline limestone. 



North Highlands, Quart. Journ. 

 Geol. Soc. vol. xv. p. 360. Sir B. I. 

 Murchison. 



Cape "Wrath, Quart. Journ. Geol. 

 Soc. vol. xvi. p. 216. 



Durness and N. W. Coast, Quart. 

 Journ. Geol. Soc. vol. xvi. p. 219. 



Isle of Lewis and Ross-shire, Quart. 

 Journ. Geol. Soc. vol. xvii. p. 175. 



5. Ireland. 



Wicklow, Wexford, and Dublin 

 Counties. 



North Highlands. 



Conglomerate-sandstone,! 2000-2500 

 chocolate-brown. J feet. 



Gneiss, fundamental, grey, with red 

 granite-veins. 



Cape Wrath. 

 Sandstones, purple-red, hard. 

 Conglomerate of subjacent gneiss. 

 Gneiss, fundamental. 



Durness and N. W. Coast ; also Isle of 



Lewis and Ross-shire. 

 Conglomerate, red, pebbles of the rock 



below. 

 Gneiss, fundamental. 



Messrs. J. B. Jukes & Wyley, Journ. 

 Geol. Soc. Dublin, vol. vi. p. 28. 



Chiefly green and purple grits, shading 

 off into quartz-rocks. 



Grits, bright red, green, grey, coarsely 

 granular, hard. 



Sandstones, compact, close - grained, 

 white mica-flakes occasionally. 



Slates, green, red, olive-brown, yellow- 

 ish, often chloritic, or a fine roofing- 

 slate or flagstone. 



(Stratification very confused.) 



These rocks are identical with those of 

 Barmouth, Wales. 



6. France. 



France. 



8. Bohemia and Germany. 



9. North America. 



10. Australia (?). 



Cotentin? (Norman Bocage). M. 

 Dalimier, Bull. Soc. Geol. Fr. n. s. 

 vol. xviii. p. 664. 



Granville, Cancale, &c. D'Archiac, 

 Bull. Soc. Geol. Fr. n. s. xviii. p. 664. 



Ardennes, Slate-quarries of Bi- 

 mogne. Bozet et Dumont. De Beau- 

 mont et Dufrenoy, Explic. de la Carte 

 Geol. de France. 



Depart. Loire. Brevenne, &c, in 

 patches. Griiner, Ann. des Mines, 

 3 me ser. vol. xix. p. 89. 



Near Maletroit, Guers, &c. Lorieux 

 and De Fourcy, Geol. Map of Morbi- 

 han. 



Upper Garonne. La Pique. Ley- 

 merie, Compt. Bend. vol. xlvi. p. 636. 



Central Bohemia. Barrande, Sil. 

 Syst. Boheme, p. 66. 



South Thuringia and Saxony. Mur- 

 cliison and Morris, Quart. Journ. Geol. 

 Soc. vol. xi. p. 412. 



Texas, Biver San Saba. B. F. Shu- 

 mard. Bull. Soc. Geol. Fr. n.s. vol. xviii. 

 p. 218. F. Boemer, 



Nebraska. F. T. Hayden, Trans. 

 Amer. Phil. Soc. n.s. vol. xii. p. 23, &e. 



Victoria, on Bivers Loddon and 

 Campaspe ? 



A. Selwyn, Quart. Journ. Geol. Soc. 

 vol. x. p. 299. 



Cotentin ? {Norman Bocage). 

 Sandstone, compact, intermixed with 

 Sandstones, purple. [schists. 



Conglomerate, felspathic materials, 

 Limestones, thin. [granitic. 



Clay-slates at St. Zo. 

 Schists, micaceous and satiny. 

 Schists, macliferous. 



Granville, Cancale, $c. 

 Schists, macliferous, with quartzites 

 and conglomerates. 



Departement de la Loire. 



Schist, argillaceous, with felspar-cry- 

 stals. Gneiss, micaceous or talcose. 

 Granite, slaty. 



Schist, green, satiny, argillaceous. 



Sandstone, green, quartzose, schistose. 



Lydian quartz, in small beds. 



Conglomerate of quartz-pebbles in si- 

 liceous cement. 



(Much disturbed by porphyry.) 



Bohemia. 

 Schists, granular and conglomeratic, 



with quartzose boulders. 

 Slates, argillaceous. 

 Schist, talcose, chloritic, micaceous. 

 Granite. 



Total 22,000 feet. 

 (No lime.) 



Texas. 



Sandstone, granitic. 

 Conglomerate, coarse granitic, 150 ft. 

 Granite. (All surmounted by fossili- 

 ferous Potsdam Sandstone.) 



Ardennes (Rimogne). 

 Quartzite, thick-bedded. 

 Psammite, alternating, thin-bedded. 

 Schists, pale. 



Schists, shining ; thickness great. 

 Schists, argillaceous and roofing. 



Near Maletroit, Guers, Sfc. 



Schist, extensive, talcose. 

 Granite, porphyritic. 



Upper Garonne. La Pique. 

 Schists, fine, satiny (extensive). 

 Gneiss. 

 Granite. 



South Thvringia and Saxony. 



Schist, chloritic, greenish, and with 



hornstone. 

 Schist, dark-coloured argillaceous. 

 Quartz-rock. 



All these beds are in great mass, and 

 are overlain conformably by Silurian. 



Nebraska. 



[Generally no Cambrian. 



Potsdam Sandstone rests extensively 



and unconformably on Azoic (Hu- 



ronian?) rocks.] 



Sandstones, ferruginous, micaceous. 



Grits, felspathic, red, grey, brown. 



Slates, clay, arenaceous, felspathic, 



Flagstones, fine arenaceous. 



Quartz-rock 1 ,, ,• 

 a , , !• alternating. 



Conglomerate f ° 



Direction N. and S., dip high. 



Gold in quartz-veins. 



No organic remains. 



Thickness 35,000 feet. 



(N.B. Probably Lower Silurian.) 



