Rock Garden

This afternoon I hauled more rocks for my rock garden, which will define one edge of the perennial border.  The larger stones I nudged onto a transfer shovel and dragged across the yard to their new resting places.  The smaller ones I hauled in the wheelbarrow.  Big or small, they're all heavy!  Tomorrow morning I'll feel like I've been beaten with a stick... or a rock.

The rock garden takes shape.

I have long been fascinated by the rocks here at Presque Isle.  As much as I complain about them, they are a significant part of the Huron Shore environment — as much as the sun and wind and cedars and deer — and many of them are things of real beauty.  Limestone, generally white or light-brown, forms the bedrock in this part of Michigan.  Visually, it's not terribly interesting.  But mixed in with the limestone are other rocks which, I feel certain, were picked up in Canada by glaciers and transported to Michigan during the Ice Age.  

Someone better versed in geology than I (it has been 45 years or so since I was in rock lab) could identify the materials pictured below.  I'll just say they are pretty.

Pretty rocks.

Close-up of a pretty rock.

And, yes, more pretty rocks.  Isn't this helpful?

Dull as our limestone is, it has one saving grace — fossils.  You don't have to look very hard around Presque Isle to find fossils.  In fact, you literally trip over them!  During the Paleozoic Era, much of Michigan was covered by warm seas inhabited by marine invertebrates such as (and this is just a guess) the Cylindrophyllum pictured below.  It's a form of coral — shown in cross-section — and dates to the Middle Devonian Period, roughly 325 million years ago.  When it died it was covered by sediment which, in due course, became the Rockport Quarry limestone (south of Lake Esau) or Rogers City limestone (north of me) which is our local bedrock.

Cylindrophyllum (?).

As for the rock garden, next spring I'll fill the voids with topsoil and then plant things, like cold-tolerant sedum (or stonecrops), which like hanging out on rocks in northern Michigan. •••