NAD Michigan - EPSG:4268

WKT

GEOGCS["GCS_North_American_Michigan", 
	DATUM["D_North_American_Michigan", 
		SPHEROID["Clarke_1866_Michigan", 6378450.047, 294.978684677]], 
	PRIMEM["Greenwich", 0.0], 
	UNIT["Degree", 0.0174532925199433]]

WKT2

GEOGCRS["GCS_North_American_Michigan", 
	DATUM["D_North_American_Michigan", 
		ELLIPSOID["Clarke_1866_Michigan", 6378450.047, 294.978684677]], 
	PRIMEM["Greenwich", 0.0], 
	CS[ellipsoidal, 2], 
	AXIS["Latitude (lat)", north, 
		ORDER[1]], 
	AXIS["Longitude (lon)", east, 
		ORDER[2]], 
	ANGLEUNIT["Degree", 0.0174532925199433], 
	ID["EPSG", "4268"]]

Data from @esri/proj-codes

{
  "wkid": 4268,
  "latestWkid": 4268,
  "macro": "PE_GCS_NAD_MICH",
  "name": "GCS_North_American_Michigan",
  "wkt": "GEOGCS[\"GCS_North_American_Michigan\",DATUM[\"D_North_American_Michigan\",SPHEROID[\"Clarke_1866_Michigan\",6378450.047,294.978684677]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]]",
  "wkt2": "GEOGCRS[\"GCS_North_American_Michigan\",DATUM[\"D_North_American_Michigan\",ELLIPSOID[\"Clarke_1866_Michigan\",6378450.047,294.978684677]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433],ID[\"EPSG\",\"4268\"]]",
  "description": "NAD Michigan",
  "authority": "EPSG",
  "version": "3.0(3.0.1)",
  "deprecated": "yes",
  "areaname": "USA - Michigan",
  "extent": {
    "slat": 41.69,
    "nlat": 48.32,
    "llon": -90.42,
    "rlon": -82.13
  }
}