EPSG:4267

BOUNDCRS[
    SOURCECRS[
        GEOGCRS["NAD27",
            DATUM["North American Datum 1927",
                ELLIPSOID["Clarke 1866",6378206.4,294.978698213898,
                    LENGTHUNIT["metre",1]]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            CS[ellipsoidal,2],
                AXIS["geodetic latitude (Lat)",north,
                    ORDER[1],
                    ANGLEUNIT["degree",0.0174532925199433]],
                AXIS["geodetic longitude (Lon)",east,
                    ORDER[2],
                    ANGLEUNIT["degree",0.0174532925199433]],
            USAGE[
                SCOPE["Geodesy."],
                AREA["North and central America: Antigua and Barbuda - onshore. Bahamas - onshore plus offshore over internal continental shelf only. Belize - onshore. British Virgin Islands - onshore. Canada onshore - Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, Nunavut, Ontario, Prince Edward Island, Quebec, Saskatchewan and Yukon - plus offshore east coast. Cuba - onshore and offshore. El Salvador - onshore. Guatemala - onshore. Honduras - onshore. Panama - onshore. Puerto Rico - onshore. Mexico - onshore plus offshore east coast. Nicaragua - onshore. United States (USA) onshore and offshore - Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin and Wyoming - plus offshore . US Virgin Islands - onshore."],
                BBOX[7.15,167.65,83.17,-47.74]],
            ID["EPSG",4267]]],
    TARGETCRS[
        GEOGCRS["NAD83(CSRS)",
            DATUM["NAD83 Canadian Spatial Reference System",
                ELLIPSOID["GRS 1980",6378137,298.257222101,
                    LENGTHUNIT["metre",1]]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            CS[ellipsoidal,2],
                AXIS["geodetic latitude (Lat)",north,
                    ORDER[1],
                    ANGLEUNIT["degree",0.0174532925199433]],
                AXIS["geodetic longitude (Lon)",east,
                    ORDER[2],
                    ANGLEUNIT["degree",0.0174532925199433]],
            USAGE[
                SCOPE["Horizontal component of 3D system."],
                AREA["Canada - onshore and offshore - Alberta; British Columbia; Manitoba; New Brunswick; Newfoundland and Labrador; Northwest Territories; Nova Scotia; Nunavut; Ontario; Prince Edward Island; Quebec; Saskatchewan; Yukon."],
                BBOX[38.21,-141.01,86.46,-40.73]],
            ID["EPSG",4617]]],
    ABRIDGEDTRANSFORMATION["NAD27 to NAD83(CSRS) (4)",
        METHOD["NTv2",
            ID["EPSG",9615]],
        PARAMETERFILE["Latitude and longitude difference file","NB2783v2.gsb"],
        USAGE[
            SCOPE["GeoNB Coordinate Transformation Service."],
            AREA["Canada - New Brunswick."],
            BBOX[44.56,-69.05,48.07,-63.7]],
        ID["EPSG",6209],
        REMARK["Introduced in 2011. Precision of 20 cm in area covered by the input data set and 40 cm anywhere else, with the exception of the northwest area of the province (near the border with Quebec) where the precision deteriorates to 80 cm."]]]

proj4.defs("EPSG:4267","+proj=longlat +datum=NAD27 +no_defs +type=crs");

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "BoundCRS",
    "source_crs": {
        "type": "GeographicCRS",
        "name": "NAD27",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "North American Datum 1927",
            "ellipsoid": {
                "name": "Clarke 1866",
                "semi_major_axis": 6378206.4,
                "semi_minor_axis": 6356583.8
            }
        },
        "coordinate_system": {
            "subtype": "ellipsoidal",
            "axis": [
                {
                    "name": "Geodetic latitude",
                    "abbreviation": "Lat",
                    "direction": "north",
                    "unit": "degree"
                },
                {
                    "name": "Geodetic longitude",
                    "abbreviation": "Lon",
                    "direction": "east",
                    "unit": "degree"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 4267
        }
    },
    "target_crs": {
        "type": "GeographicCRS",
        "name": "NAD83(CSRS)",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "NAD83 Canadian Spatial Reference System",
            "ellipsoid": {
                "name": "GRS 1980",
                "semi_major_axis": 6378137,
                "inverse_flattening": 298.257222101
            }
        },
        "coordinate_system": {
            "subtype": "ellipsoidal",
            "axis": [
                {
                    "name": "Geodetic latitude",
                    "abbreviation": "Lat",
                    "direction": "north",
                    "unit": "degree"
                },
                {
                    "name": "Geodetic longitude",
                    "abbreviation": "Lon",
                    "direction": "east",
                    "unit": "degree"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 4617
        }
    },
    "transformation": {
        "name": "NAD27 to NAD83(CSRS) (4)",
        "method": {
            "name": "NTv2",
            "id": {
                "authority": "EPSG",
                "code": 9615
            }
        },
        "parameters": [
            {
                "name": "Latitude and longitude difference file",
                "value": "NB2783v2.gsb",
                "id": {
                    "authority": "EPSG",
                    "code": 8656
                }
            }
        ],
        "id": {
            "authority": "EPSG",
            "code": 6209
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=longlat +datum=NAD27 +no_defs +type=crs">
	<Layer srs="+proj=longlat +datum=NAD27 +no_defs +type=crs">
	</Layer>
</Map>