From the book:

Simple double-crochet shells worked in stripes of sea and sand colors are as soothing as ocean waves lapping the shore.

The pattern specifies: Chunky-weight acrylic yarn, approximately:

• 42 oz (1680 yards / 1536 meters) cream, MC
• 15 oz (600 yards / 549 meters) green, A
• 15 oz (600 yards / 549 meters) tan, B

Gauge: 4 shells = 3.5” and 8 rows = 4”

The afghan is worked in 138 rows, with a two-round border. The pattern begins on page 10.