The Seattle series is a deep, very poorly drained organic soil formed in depressions in both river valleys and on drift uplands.
(The Seattle series; is; a deep, very poorly drained organic soil formed in depressions in both river valleys and on drift uplands) (a deep, very poorly drained organic soil; formed; L:in depressions in both river valleys and on drift uplands)
The Seattle series a deep, very poorly drained organic soil
is formed
a deep, very poorly drained organic soil formed in depressions in both river valleys and on drift uplands
L:in depressions in both river valleys and on drift uplands