THE HIGHLAND BORDER ROCKS OF THE ABERFOYLE DISTRICT. 
211 
Siphonotreta aff. scotica, Dav. (See p. 191.) 
Fig. 18. Cast of interior of ventral valve with part of rim of exterior of the valve. 
Fig. 18a. Drawing (enlarged) of above. 
1 Schizambon, W alcott. (Seep. 191.) 
Fig. 19. Interior of dorsal valve. 
Fig. 19a. Drawing (enlarged) of above. 
Lingulella aff. ferruginea, Salter. (See p. 189.) 
Fig. 20. Cast of interior of dorsal valve above and portion of interior of ventral valve below. 
Fig. 21. Interior of ventral valve. 
Fig. 22. Exterior of ventral valve. 
Lingulella ail. nicholsoni, Calloway. (See p. 189.) 
Fig. 23. Interior of dorsal valve ; shell distorted and broken. 
Photographs all magnified 5 diameters. Magnification of- drawings 17 a, 18a, 19a as shown on Plate. 
Figs. 17a, 18a, 19a, and the insets to figs. 2, 4, 5, are from drawings by Dr Peach. All the other figures 
are from untouched photographs. 
Plate II. 
Graptolitoidea. (See p. 187.) 
Fig. 1. A Diplograptid — Trigonograptus or Cryptograptus. x 6|. 
Fig. 1a. Counterpart of specimen shown in fig. 1. x 6^-. 
Fig. 2. A Diplograptid — Trigonograptus or Cryptograptus. x 5. 
Fig. 2a. Counterpart of specimen shown in fig. 2. x 5. 
Fig. 2b. Same specimen as that shown in fig. 2a. x 7. 
Phyllocarida. (See p. 191.) 
Fig. 3. Modiolocaris dalcynsi, Peach, x 5. 
Fig. 3a. Drawing of above. 
Incertx sedis. (Seep. .192.) 
Fig. 4. Fragment of some Arthropod. x 5. 
Fig. 5. Punctate stain of some Arthropod. ' x 5. 
Fig. 6. Jaw of an Annelid or one of the chelicerse of an Arthropod. x 5. 
Fig. 6a. Drawing of above (slightly enlarged as compared with fig. 6). 
Figs. 7 and 8. Cercopods of a Phyllocarid Crustacean. x 5. 
Fig. 9. Triangular plate, pitted, of an unknown form, x 5, 
The Aberfoyle Limestone. 
Fig. 10. Photograph of a hand specimen showing the columnal of a Crinoid. x 6. 
Fig. 11. Photomicrograph of thin section of rock showing organisms. x 10. (See No. 1, p. 193.) 
Fig. 12. Photomicrograph of thin section of rock showing organisms, x 25. (See No. 5, p. 193.) 
Fig. 13. Photomicrograph of thin section of rock showing organisms, x 25, (See No. 2, p. 193.) 
Figs. 3a and 6a are from drawings by Dr Peach. All the other figures are from untouched photographs. 
Plate III. 
Photomicrographs of Roeks. 
Fig. 1. Variolitic spilite, Gualann, magnified 25 diameters. The variolitic arrangement of the albite 
laths is well seen. (See p. 181.) 
Fig. 2. Breccia from exposure about J mile north-east of the ruins of Bofrishlie Farm, magnified 
10 diameters. The white grains are quartz; the elliptical grain in the upper portion of the figure is ortho- 
clase ; the fragments with irregular margins are palagonite ; the angular and subangular pieces of fine- 
grained sediments are cherty shales and mudstones. (See p. 183.) 
TRANS. ROY. SOC. EDIN., VOL. LII, PART I (NO. 9). 
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