Lateral adjustment lever with patent dates 10-21-84 &7-24-88. The planes were identical to the original Stanleys, except for the markings on the beds, (W.., K..), Keen Kutter and Winchester trademarks on the blades and frogs with twisted lateral levers.
"S" casting mark on bed (raised dot on some specimens). Frogs with "B" casting marks. During the 1920's, Stanley manufactured Type 4 Bed Rock Planes, for Keen Kutter and Winchester.
This would also mean that fossils found in the deepest layer of rocks in an area would represent the oldest forms of life in that particular rock formation.
In reading Earth history, these layers would be read from bottom to top or oldest to most recent.
If certain fossils are typically found only in a certain rock unit and are found in many places worldwide, they may be useful as index or guide fossils in finding the age of undated strata.
By using this information from rock formations in various parts of the world and correlating the studies, scientists have been able to construct the geologic time scale: This relative time scale divides the vast amount of Earth history into various sections based on geological events (sea encroachments, mountain-building, and depositional events), and notable biological events (appearance, relative abundance, or extinction of certain life forms).
I recently obtained an original copy of a 1923 Stanley promotional pamphlet which illustrates and describes the Bed Rock Planes in production at that time.
All of the fossils represented would be found in sedimentary rocks of marine origin.