I collect round embossed amber milk bottles. The only Michigan item I'm aware of is a buttermilk quart from Emblagard Dairy from Marquette. Both Tutton & Fisher list this bottle in their books, but I've not even seen a picture of one.
Here’s what I’ve dug just this year minus a blank slug plate quart milk I haven’t cleaned up yet. I’m not much of a milk bottle collector but I have a few. The Sunnybrook Dairy would be my most rare milk. Cathro is just a ghost town now and I’ve never came across another milk bottle from there. It could possibly be the only one known in the one pint size. I was told there is a quart version of that bottle listed in the Michigan milk book.
This one is a bottom embossed milk out of Detroit pre 1915. I believe it’s embossed J W Ladd Co. I’m hunting right now and don’t have access to it at the moment to confirm that.
My Michigan Milk Bottle Book shows 5 different C.E. Posey a.k.a Marine City Dairy. I got a few different Michigan Milks, Most I dug myself. Here's one from a very small obscure ghost town only a couple of miles west of Marine City. The Elms LeCLARE'S from Starville Michigan. I've been through this town a few times. Not even a town, just a Intersection with Church & Cemetary on one Corner & Gas Station on other Corner. Population of maybe 5 people at most in a 5 square mile area. LEON.