Figure 9. Paucicrura rogata (Sardeson, 1890 ) from the Verulam Formation (Chatfieldian) at Lake Simcoe, Ontario. ROM IP67553. ( 1 ) Dorsal view; ( 2 ) posterior view; ( 3 ) posterior close-up showing first-formed shells. Arrow points to dorsal first-formed shell. Scale bars are ( 1, 2 ) 5 mm

Figure 4 Bathyurus ( Raymondites ) ingalli (Raymond, 1913 ), Verulam Formation, right bank of the Moira River, Belleville, Hastings County, southern Ontario. (1–3), incomplete pygidium showing axial spine (ROM 35352), dorsal, lateral and anterior views, ×5

Figure 3. Local stratigraphy of the Verulam Formation, showing distribution of the bentonite, its NW-directed disappearance, and core and outcrop locations (inset map) shown relative to general local geology (based on Williams et al., 1984 ). The letters s and c associated with the Nepean Point

TABLE 1. BIOTITE CHEMISTRY, VERULAM FORMATION

TABLE 2. MAJOR-OXIDE AND SELECTED TRACE-ELEMENT GEOCHEMISTRY, VERULAM FORMATION

Fig. 7. Field Photographs of the upper Kirkfield Formation and lower Verulam Formation. ( a ) The contact between the middle and upper members of the Kirkfield Formation. Red arrow indicates the approximate position of the lower mounded hardground. Note the strong backstepping pattern between

Figure 4. Outcrop and core photographs illustrating typical stratigraphic fabric and lithofacies of the Verulam Formation: (A) Interbedded shale (dark) and limestone (light) typical of the upper Verulam Formation. The interval shown is from the Lebreton core, and is stratigraphically equivalent

to the Verulam Formation), north of west red brick house, Ange Gardien road, 4 miles (6.4 km) west of LOriginal’, Ontario. (C–G) Dorsal, ventral, anterior, posterior, and lateral views, respectively; W-MI 2, Verulam Formation, Manitoulin Island. (H–L) Dorsal, ventral, anterior, posterior, and lateral views

Figure 2. Stratigraphy and general lithology of the Upper Ordovician succession in the Ottawa Embayment, including the lower (l) and upper (u) division of the Verulam Formation, compared to the equivalent platform-to-basin transition and stratigraphic sequences (M4–6, C1) of central to eastern

Fig. 13. Tracings of serial sections of specimens W-MI5 ( Plaesiomys browni ) from the Verulam Formation on Manitoulin Island. Measurements refer to distance from the most posterior point on the dorsal umbo.

Figure 3 Achatella achates (Billings, 1860 ) from Ontario. ( 1–4 ) Enrolled exoskeleton (ROM 49475), dorsal, ventral, lateral and anterior views, ×7, Verulam Formation, Gamebridge Quarry, Gamebridge; ( 5 ) complete, somewhat compacted exoskeleton (GSC 1784, holotype), ×3.75, Lindsay Formation

, lateral and posterior views, ×10, Verulam Formation, Gamebridge Quarry, upper face.

andesite through basaltic andesite source. The upper Indian Castle (shale-hosted) bentonites lie intermediate to the compacted shale suite from the Verulam Formation and the bentonite samples. This suggests that there may be some progressive dilution of volcanic signatures. (D) Discrimination diagram

(shaded, n = 3) associated with the bentonite (see Fig. 5 ), with the black line denoting RU4, the limestone interbed; 3—Permian limestone; 4—Devonian microbialite; 5—Pacific seawater (×10 5 ) 0–1000 m water depth. Lower: Samples of compacted gray shale typical of the upper Verulam Formation normalized