NGVD29 depth (US Feet) - EPSG:6359

WKT

VERTCS["NGVD29_depth", 
	VDATUM["National_Geodetic_Vertical_Datum_1929"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", -1.0], 
	UNIT["Foot_US", 0.3048006096012192]]

WKT2

VERTCRS["NGVD29_depth", 
	VDATUM["National_Geodetic_Vertical_Datum_1929"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", down, 
		LENGTHUNIT["Foot_US", 0.3048006096012192]], 
	ID["EPSG", "6359"]]

Data from @esri/proj-codes

{
  "wkid": 6359,
  "latestWkid": 6359,
  "macro": "PE_VCS_NGVD29_D",
  "name": "NGVD29_depth",
  "wkt": "VERTCS[\"NGVD29_depth\",VDATUM[\"National_Geodetic_Vertical_Datum_1929\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",-1.0],UNIT[\"Foot_US\",0.3048006096012192]]",
  "wkt2": "VERTCRS[\"NGVD29_depth\",VDATUM[\"National_Geodetic_Vertical_Datum_1929\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",down,LENGTHUNIT[\"Foot_US\",0.3048006096012192]],ID[\"EPSG\",\"6359\"]]",
  "description": "NGVD29 depth (US Feet)",
  "authority": "EPSG",
  "version": "8.2.7(10.3.1)",
  "deprecated": "no",
  "areaname": "USA - CONUS - onshore",
  "extent": {
    "slat": 24.41,
    "nlat": 49.38,
    "llon": -124.79,
    "rlon": -66.91
  }
}