Table 3. Key for Identification of Common Sandy Shales and Sandy Fireclays.

Step 1.0 Examine the side of the core to determine the size, shape and proportion of sandy units that are interbedded with shaley material.

1.1 If the rock-

consists of layers of sandstone and shale with sandstone proportions varying between about 80% and 20% (e.g. 50L), proceed to step 2.0. (35R is slightly above the upper limit of sandstone proportion; 56R is slightly below the lower limit.)

1.2 If it-

consists mostly of shale with streaks of sandstone making up between 20% and 1% of the rock (e.g. 55R), proceed to step 3.0. (56R represents the upper limit for abundance of sandstone streaks.)

1.3 If it-

is essentially massive as in specimen 58L (some may have vague layers or wisps of sandy material, e.g. 60L ), proceed to step 4.0.

1.4 If it-

consists of spots, lumps or tube-like bodies of sandstone or shale (e.g. 63L), proceed to step 5.0.

Step 2.0 Examine the side of the core to determine the shape of the sandy layers and the color of the interbedded shale.

2.1 If the sandy layers are-

wedge or ripple shaped and the interbedded shale is black (e.g. 50L), the rock is a Black Shale and Interbedded Sandstone, Rippled or 312 R I P.

2.2 If they are-

wedge or ripple shaped and the interbedded shale is dark gray (e.g. 51R), the rock is a Dark Gray Shale and Interbedded Sandstone, Rippled or 322 RIP.

2.3 If they are-

wedge or ripple shaped and the interbedded shale is light gray or light greenish gray (e.g. 53R), the rock is a Light Gray Green Shale and Interbedded Sandstone, Rippled or 332 RIP.

2.4 If they are-

essentially uniform and parallel and the interbedded shale is dark gray (e.g. 54L), the rock is a Dark Gray Shale and Interbedded Sandstone, Flat or 322 FLT.

Step 3.0 Examine the side of the core to determine the color of the shaley material between the sandstone streaks.

3.1 If the color is-

black (e.g. 55L), the rock is a Black Shale with Sandstone Streaks or 313.

3.2 If it is-

dark gray (e.g. 57L), the rock is a Dark Gray Shale with Sandstone Streaks or 323.

3.3 If it is-

light gray or light greenish gray (e.g. 57R), the rock is a Light Gray Green Shale with Sandstone Streaks or 333.

Step 4.0 Examine the side of the core for faint traces of bedding. Break the core and examine the fracture pattern of the broken butt end.

4.1 If the rock shows-

faint traces of layering at right angles to the sides of the core as on 59L, and the broken butt end shows a planar surface similar to that on upper 66L, determine the color of the rock and proceed below:

1. If the color is dark gray (e.g. 58L), the rock is a Dark Gray Massive Sandy Shale or 324.*
2. If it is light gray or light greenish gray (e.g. 59R), the rock is a Light Gray Green Massive Sandy Shale or 334.

4.2 If it shows-

faint wispy, irregular lines or spots on the sides of the core as on 60R or irregular fracture on the butt end similar to that on lower 66L, determine the color of the rock and proceed below:

1. If the color of the rock is dark gray (e.g. 60L), the rock is a Dark Gray Massive Churned Sandy Shale or 325.*
2. If it is light gray or light greenish gray (e.g. 60R), the rock is a Light Gray Green Massive Churned Sandy Shale or 335.

Step 5.0 Examine the side of the core to determine the character of the linear or circular bodies. Break the core and examine the fracture pattern of the broken butt end.

5.1 If this examination shows-

that the linear or circular bodies are sheathed in carbonaceous material and the broken butt end of the core shows a highly irregular fracture surface, determine the color of the rock and proceed below:

1. If the color is dark gray (e.g. 61L), the rock is a Dark Gray Sandy Fireclay or 327.
2. If it is light gray or light greenish gray (e.g. 62R), the rock is a Light Gray Green Sandy Fireclay or 337.

5.2 If it shows-

that the linear or circular bodies do not have carbonaceous films and that the fractured butt ends are essentially flat with a few white sandy spots (e.g. 63L), the rock is a Dark Gray Burrowed Sandy Shale or 328.*

5.3 If it shows-

that the precise character of the spots, tubes or mottling cannot be determined, the rock is a Dark Gray Churned Sandy Shale or 326.*

*These rocks in some cases contain fossil shells. Please see page 79.