Schedule for Field Description of Sedimentary Rocks 
Note. — Define all terms that might be at all uncertain. Use metric units if 
possible. Describe first the largest units recognized, then those of the next order, 
and so on down to the smallest. 
A. External form of the rock unit. Lenticular, persistent, very regular 
in thickness, etc. ; dimensions. 
B. Color. Color of unit as a whole, wet or dry, according to Kidgway or 
Munsell color system, or color card of this committee. 
C. Bedding. 
1. How manifested: Sharp, by partings, by difference in texture, 
color, etc. ; transitional; shaly (see introductory note). 
2. Shape of bedding surfaces: Plane, undulating, ripple-marked, etc.; 
irregular; if not plane, give details of form and dimensions of features. 
8. Thickness of beds: Comparative thicknesses; different orders. 
Relation of thicknesses; rhythmic; random. If variable, relation 
between thickness and composition, bedding, etc. 
4. Attitude and direction of bedding surfaces: Horizontal, inclined, 
curved. Relation to each other: Parallel, intersecting, tangential; 
angles between different attitudes and directions; dips, strikes ; dimen- 
sions ; relation of size, composition, shape, etc., to attitude and direc- 
tion; relation of composition to different types of bedding. 
5. Markings of bedding surfaces: Mud cracks, rain prints, bubble 
impressions, ice-crystal impressions, trails, footprints, etc. 
6. Disturbances of bedding: Edgewise or int informational conglom- 
erates, folding or crumpling of individual beds before consolidation, etc. 
D. Composition. 
1. Inorganic constituents. 
a. Mineralogy or lithology of principal constituents. 
b. Size: Prevailing size if fairly uniform; range in sizes if 
not; proportions of different sizes as determined by sieving 
where feasible; distribution of sizes with relation to other 
features; vertical and lateral variations in size. 
e. Shape: Crystalline (automorpbic), angular, subangular, 
subrounded, rounded; relation of shape to size, material, posi- 
tion in beds, etc. For quantitative results on pebbles, etc., esti- 
mate or measure radius of curvature of sharpest edge, mean 
radius, and maximum and minimum diameter. 
