MONOGRAPTUS. 425 



Quarry, Glyn Ceiriog ; Caer Drewyn, Rhayader Road, near Builth Road Station; 

 Castle Crab, near Builth Road ; Grove Cottages, Builth Road ; River Ithon, N.E. 

 of Newbridge. Shropshire: Walcot Quarry, near Chirbury. Lalce District: 

 Middle and Near Gill, Cautley ; River Rawthey ; Wandale Hill, etc. 



Associates, etc. — Monog. riccartonensis makes its first appearance towards the 

 top of the zone of Cyrtog. Murchisoni, where it is as a rule rather short and is 

 associated with the zone fossil, M. priodon, M. vomerinus, etc. It is, however, rather 

 rare at this horizon but comes in abundantly in the rocks above, where it is 

 characteristically long and. limp, and is associated with the earliest forms of M. 

 (I iihi us; other associates at this higher horizon are M. priodon, M. vomerinus and 

 M. capillaceus, but as M. riccartonensis is often found hereabout to the exclusion 

 of every other form it is taken by Elles and others as the index fossil of the zone. 



( 'ollections.— Geological Survey of Scotland, Sedgwick Museum, Lapworth, 

 and the Authors. 



Monograptus Flemingii (Salter). Plate XLII, figs. 5 a— d. 



1852. Graptolithus Flemingii, Salter, Quart. Journ. Geol. Soc, vol. viii, p. 390, pi. xxi, figs. 5 a, b, 



6, 7 a, b. 

 1876. Monograptus Flemingii, Lapworth, Geol. Mag. [2], vol. iii, p. 504, pi. xx, fig. 8. 

 1833. Monograptus Flemingii, Tullberg, Skftnes G-rapt., Svensk. Geol. Undersokn., ser. C, no. 55, 



p. 23, pi. ii, fig. 25. 

 1900. Monograptus Flemingii, var. [3 and var. <5, Elles, Quart. Journ. Geol. Soc., vol. lvi, p. 402, figs. 



11 and 14. 



Polypary straight, or slightly flexed, attaining a length of 17 cm. or more, 



with recurved proximal portion, widening gradually to a maximum breadth 



of 2*5 mm., which is then maintained. Sicnla relatively small. Thecse 



fourteen to nine in 10 mm., with abruptly narrowing apertural region; 



aperture commonly furnished below with a short claw or spine, giving the 



appearance of a beak or rostrum, the whole beak occupying from one-fifth 



to one-third the total breadth of the polypary. 



Description . — The polypary is of considerable length and is usually found in a 



fragmentary state. These fragments, if short, may appear approximately straight, 



but if fairly long, show the flexure characteristic of the species. 



The sicula has a length of about 1'6 mm. and shares in the reflexure of the 

 whole proximal end ; it is furnished with a short stiff virgella. 



The thecas vary someAvhat in different parts of the polypary ; usually about one- 

 half of the thecal length is involved in the beak-like hook, which proximally is so 

 small that it occupies only one-fifth of the breadth of the polypary ; this amount, 

 however, increases up to one-third in the distal portion. The thecae are set far more 

 closely in the proximal than in the distal portion. 



